Women's preferences for men's beards show no relation to their ovarian cycle phase and sex hormone levels. Barnaby J.W. Dixson et al. Hormones and Behavior, Volume 97, January 2018, Pages 137–144. https://doi.org/10.1016/j.yhbeh.2017.11.006
Highlights
• The first study testing whether hormonal variation among women is associated with preferences for men's beardedness
• Results showed that preferences did not change over the menstrual cycle.
• Preferences were also unrelated to changes in estradiol and progesterone over the menstrual cycle.
• Our results suggest that women's preferences for men's beardedness may not change with fecundability.
Abstract: According to the ovulatory shift hypothesis, women's mate preferences for male morphology indicative of competitive ability, social dominance, and/or underlying health are strongest at the peri-ovulatory phase of the menstrual cycle. However, recent meta-analyses are divided on the robustness of such effects and the validity of the often-used indirect estimates of fertility and ovulation has been called into question in methodological studies. In the current study, we test whether women's preferences for men's beardedness, a cue of male sexual maturity, androgenic development and social dominance, are stronger at the peri-ovulatory phase of the menstrual cycle compared to during the early follicular or the luteal phase. We also tested whether levels of estradiol, progesterone, and the estradiol to progesterone ratio at each phase were associated with facial hair preferences. Fifty-two heterosexual women completed a two-alternative forced choice preference test for clean-shaven and bearded male faces during the follicular, peri-ovulatory (validated by the surge in luteinizing hormone or the drop in estradiol levels) and luteal phases. Participants also provided for one entire menstrual cycle daily saliva samples for subsequent assaying of estradiol and progesterone. Results showed an overall preference for bearded over clean-shaven faces at each phase of the menstrual cycle. However, preferences for facial hair were not significantly different over the phases of menstrual cycle and were not significantly associated with levels of reproductive hormones. We conclude that women's preferences for men's beardedness may not be related to changes in their likelihood of conception.
Keywords: Facial attractiveness; Menstrual cycle; Facial hair; Sexual selection
Monday, December 11, 2017
Neurobiology of Gender Identity and Sexual Orientation
Roselli, C. E. (), Neurobiology of Gender Identity and Sexual Orientation. J Neuroendocrinol, e12562. Accepted Author Manuscript. doi:10.1111/jne.12562
Abstract: Sexual identity and sexual orientation are independent components of a person's sexual identity. These dimensions are most often in harmony with each other and with an individual's genital sex, but not always. This review discusses the relationship of sexual identity and sexual orientation to prenatal factors that act to shape the development of the brain and the expression of sexual behaviors in animals and humans. One major influence discussed relates to organizational effects that the early hormone environment exerts on both gender identity and sexual orientation. Evidence that gender identity and sexual orientation are masculinized by prenatal exposure to testosterone and feminized in it absence is drawn from basic research in animals, correlations of biometric indices of androgen exposure and studies of clinical conditions associated with disorders in sexual development. There are, however, important exceptions to this theory that have yet to be resolved. Family and twin studies indicate that genes play a role, but no specific candidate genes have been identified. Evidence that relates to the number of older brothers implicates maternal immune responses as a contributing factor for male sexual orientation. It remains speculative how these influences might relate to each other and interact with postnatal socialization. Nonetheless, despite the many challenges to research in this area, existing empirical evidence makes it clear that there is a significant biological contribution to the development of an individual's sexual identity and sexual orientation.
Abstract: Sexual identity and sexual orientation are independent components of a person's sexual identity. These dimensions are most often in harmony with each other and with an individual's genital sex, but not always. This review discusses the relationship of sexual identity and sexual orientation to prenatal factors that act to shape the development of the brain and the expression of sexual behaviors in animals and humans. One major influence discussed relates to organizational effects that the early hormone environment exerts on both gender identity and sexual orientation. Evidence that gender identity and sexual orientation are masculinized by prenatal exposure to testosterone and feminized in it absence is drawn from basic research in animals, correlations of biometric indices of androgen exposure and studies of clinical conditions associated with disorders in sexual development. There are, however, important exceptions to this theory that have yet to be resolved. Family and twin studies indicate that genes play a role, but no specific candidate genes have been identified. Evidence that relates to the number of older brothers implicates maternal immune responses as a contributing factor for male sexual orientation. It remains speculative how these influences might relate to each other and interact with postnatal socialization. Nonetheless, despite the many challenges to research in this area, existing empirical evidence makes it clear that there is a significant biological contribution to the development of an individual's sexual identity and sexual orientation.
Hot or not? How self-view threat influences avoidance of attractiveness feedback
Hot or not? How self-view threat influences avoidance of attractiveness feedback. Jennifer L. Howell, Kate Sweeny, Wendi Miller & James A. Shepperd. Self and Identity, https://doi.org/10.1080/15298868.2017.1401552
Abstract: In two studies, we examined whether people’s decision to receive evaluations of their own attractiveness depended on whether the evaluations came from sources that might threaten their self-views. Participants believed that evaluators rated their attractiveness based on a photograph taken earlier and ostensibly uploaded to a website. Participants then received the opportunity to view the attractiveness ratings from the evaluators. In both studies, and in a meta-analysis including two pilot studies that are reported in Supplemental Materials online, participants – particularly women – rated feedback as more threatening and avoided receiving feedback more when the ratings came from high-threat evaluators (university peers) than from low-threat evaluators (students at another university, older adults, or children). The robustness of this overall effect was confirmed in the meta-analysis. These results suggest that self-view threat can prompt information avoidance.
Keywords: Information avoidance, self-view threat, attractiveness
Abstract: In two studies, we examined whether people’s decision to receive evaluations of their own attractiveness depended on whether the evaluations came from sources that might threaten their self-views. Participants believed that evaluators rated their attractiveness based on a photograph taken earlier and ostensibly uploaded to a website. Participants then received the opportunity to view the attractiveness ratings from the evaluators. In both studies, and in a meta-analysis including two pilot studies that are reported in Supplemental Materials online, participants – particularly women – rated feedback as more threatening and avoided receiving feedback more when the ratings came from high-threat evaluators (university peers) than from low-threat evaluators (students at another university, older adults, or children). The robustness of this overall effect was confirmed in the meta-analysis. These results suggest that self-view threat can prompt information avoidance.
Keywords: Information avoidance, self-view threat, attractiveness
On the Dynamics of Ideological Identification: The Puzzle of Liberal Identification Decline
On the Dynamics of Ideological Identification: The Puzzle of Liberal Identification Decline. Elizabeth Coggins and James A. Stimson. Political Science Research and Methods, https://doi.org/10.1017/psrm.2017.38
Abstract: Our focus is a puzzle: that ideological identification as “liberal” is in serious decline in the United States, but at the same time support for liberal policies and for the political party of liberalism is not. We aim to understand this divorce in “liberal” in name and “liberal” in policy by investigating how particular symbols rise and fall as associations with the ideological labels “liberal” and “conservative.” We produce three kinds of evidence to shed light on this macro-level puzzle. First, we explore the words associated with “liberal” and “conservative” over time. Then we take up a group conception by examining the changing correlations between affect toward “liberals” and affect toward other groups. Finally, we consider the changing policy correlates of identification.
Abstract: Our focus is a puzzle: that ideological identification as “liberal” is in serious decline in the United States, but at the same time support for liberal policies and for the political party of liberalism is not. We aim to understand this divorce in “liberal” in name and “liberal” in policy by investigating how particular symbols rise and fall as associations with the ideological labels “liberal” and “conservative.” We produce three kinds of evidence to shed light on this macro-level puzzle. First, we explore the words associated with “liberal” and “conservative” over time. Then we take up a group conception by examining the changing correlations between affect toward “liberals” and affect toward other groups. Finally, we consider the changing policy correlates of identification.
How Culture Affects Depression: Insight into culture's multifaceted influence on depression
How Culture Affects Depression: Insight into culture's multifaceted influence on depression. Marianna Pogosyan, Psychology Today, Dec 06, 2017
https://www.psychologytoday.com/blog/between-cultures/201712/how-culture-affects-depression
"All happy families are alike, each unhappy family is unhappy in its own way," Leo Tolstoy.
Poets and philosophers have long mused about the universal and idiosyncratic signature of our emotions. The human family shares a similar biology. Yet, culture leaves an undeniable imprint on our emotional narratives, including the way we feel and think of distress, how it manifests and how we cope with it. In her cross-cultural research on depression, psychologist Yulia Chentsova-Dutton likens depression’s constellations of symptoms to the starry sky. It’s the same universal experience of suffering, the same black vastness above our heads dotted with bright and dim lights. However, when we look at the night sky, as with the expression of depression around the world, we might notice some stars and miss others depending on where we are.
Here is Dr. Chentsova-Dutton in her own words on culture’s multifaceted influence on depression:
What are some causes of depression across cultures?
Many of the risk factors for depression are similar across cultures. These include gender, unemployment, traumatic events. The themes of depression tend to revolve around loss. But what people make of their losses and how they interpret their distress differs tremendously across cultures. In the West, we have increasingly pathologized depression and attributed it to biomedical factors. We tend to think that distancing people from their distress can be a functional way of helping them. However, teaching people that this very complex social, cultural, and biological phenomenon is entirely biological can backfire. It encourages people to ignore environmental factors, and instead, essentialize depression as a characteristic of themselves and their biology.
How does the meaning of depression vary around the world?
The meaning that people assign to suffering varies richly across cultures. Buddhism approaches suffering as an essential characteristic of life. We are mindful of it, yet, we don't try to chase it away. In Eastern European Orthodox Christianity and traditional Catholic contexts, there are two religious perspectives on suffering. On one hand, excessive suffering that blocks your goals is thought to be a sin. Simultaneously, suffering that allows you to stay engaged in your life is thought to bring you closer to God. It’s almost like broadcasting your suffering highlights you as a more complex and virtuous human being in other people’s eyes. Moreover, in India and Ecuador suffering can be interpreted as a rift in social networks that requires mending.
Should there be culture-specific approaches to depression?
We have evidence that public education efforts to teach people in non-western countries how to be properly depressed western-style result in changes in how people think about their distress. In Japan, for example, pharmaceutical companies once engaged in a systematic campaign to train people to recognize both major and minor depression as problems (“a cold of the soul”). I can imagine if somebody is suffering and finally there is a label, they might get treatment, which would be a positive outcome. I can also imagine people who have formerly obtained support and would have done well through the use of social networks and traditional mood regulation, are now thinking of themselves as sick. The older immigrants have a lot of cultural wisdom. Why do we assume that our knowledge is best for them, instead of learning from them and understanding how they cope? It’s a major direction for research for the next decades.
Are there genetic vulnerabilities for depression across cultures?
Genetic vulnerability differs substantially from country to country. East Asian contexts, for example, show a high prevalence of genes associated with depression. Yet, despite these vulnerabilities, they develop fewer cases of the disorder. One hypothesis is that genetic vulnerabilities have co-evolved with culture, creating extra protective factors (in this case, extra interdependence). However, when these people leave their cultural contexts, they have a higher risk of developing depression.
What factors protect against depression?
Social stability and functional relationships are big protective factors against depression. East Asian contexts promote stable social networks. For example, most adults in Japan are still in frequent contact with someone they have known since childhood. In countries like the U.S., that’s rarer because of high mobility levels. (Of course, it depends on the quality of the relationships: if you are stuck with people who create tensions for you, it can be problematic.) Another leading hypothesis is that some cultures reinforce ways of regulating emotions that may be more functional than others. Finally, by virtue of prioritizing emotions and personal happiness, in contexts like the U.S., we are creating a discrepancy between how we feel and how we are supposed to feel. This can lead to additional problems.
What is the role of emotion regulation?
Emotion regulation is increasingly becoming understood as a core factor in all affective disorders. In western societies, we don't see enough adaptive strategies like reappraisal: learning to tell yourself a different story that would eventually lead to different emotions. There is also not enough social regulation of emotion, which occurs by sharing our emotions with others. Research shows that cultures can facilitate functional regulation strategies. For example, Igor Grossmann’s work shows that Russians make rumination (generally considered a dysfunctional strategy) more functional by encouraging people to ruminate about the self from another person’s perspective, making rumination almost reappraisal-like in its quality.
How do symptoms of depression differ across cultures?
Best studied differences in expression of depression are whether symptoms are primarily experienced in the body, or as disorders of emotions and cognitions. In the U.S., we officially look for both, with an emphasis on affective features; you can’t be diagnosed with depression unless you have either depressed mood or anhedonia (lack of pleasure). On the other hand, research based on Chinese samples shows that people there are more likely to experience and express depression as bodily symptoms: the person is tired and not sleeping, they don't have energy and aren’t concentrating well. Historically, it’s the diagnosis of neurasthenia (weakness of the nerves), which migrated to China from Europe via the Soviet Union. Essentially, it’s major depression without the affective features.
How is depression assessed across cultures?
People don't seek help in the same manner, and help is not available in the same way. Moreover, the extent to which symptoms are recognized as pathology vs. an unpleasant but normative characteristic of life might differ. Assessment is a challenge in part because many of our assessment tools are based on the western set of criteria. Because of commonalities, we might catch some symptoms, but we might also miss presentations of the disorder that look different. We have started to develop tools that incorporate locally meaningful symptoms.
How do treatment methods differ across cultures?
Pharmaceutically, we know that prescriptions and doses need to be altered based on various factors, including ethnicity. There is accumulating data showing that some approaches that are effective in the U.S. (e.g., cognitive-behavioral therapy) are also looking promising in other cultures. Similarly, mindfulness approaches from the East have been found to be effective in western samples. We have this idea of therapy as individual-based, yet we know from research that having somebody next to you, even if you don't discuss your problems, is regulatory. Thus, approaches that make use of social ties have a lot of promise, particularly outside highly individualistic contexts. I’m hoping that this gap in clinical science will get increasingly filled and we will enrich our toolset of approaches for treating depression.
Many thanks to Yulia Chentsova-Dutton for being generous with her time and insights. Dr. Chentsova-Dutton is an Associate Professor of Psychology at Georgetown University and the head of the Culture and Emotions lab.
Marianna Pogosyan, Ph.D., is an intercultural consultant specializing in the psychology of cross-cultural transitions.
https://www.psychologytoday.com/blog/between-cultures/201712/how-culture-affects-depression
"All happy families are alike, each unhappy family is unhappy in its own way," Leo Tolstoy.
Poets and philosophers have long mused about the universal and idiosyncratic signature of our emotions. The human family shares a similar biology. Yet, culture leaves an undeniable imprint on our emotional narratives, including the way we feel and think of distress, how it manifests and how we cope with it. In her cross-cultural research on depression, psychologist Yulia Chentsova-Dutton likens depression’s constellations of symptoms to the starry sky. It’s the same universal experience of suffering, the same black vastness above our heads dotted with bright and dim lights. However, when we look at the night sky, as with the expression of depression around the world, we might notice some stars and miss others depending on where we are.
Here is Dr. Chentsova-Dutton in her own words on culture’s multifaceted influence on depression:
What are some causes of depression across cultures?
Many of the risk factors for depression are similar across cultures. These include gender, unemployment, traumatic events. The themes of depression tend to revolve around loss. But what people make of their losses and how they interpret their distress differs tremendously across cultures. In the West, we have increasingly pathologized depression and attributed it to biomedical factors. We tend to think that distancing people from their distress can be a functional way of helping them. However, teaching people that this very complex social, cultural, and biological phenomenon is entirely biological can backfire. It encourages people to ignore environmental factors, and instead, essentialize depression as a characteristic of themselves and their biology.
How does the meaning of depression vary around the world?
The meaning that people assign to suffering varies richly across cultures. Buddhism approaches suffering as an essential characteristic of life. We are mindful of it, yet, we don't try to chase it away. In Eastern European Orthodox Christianity and traditional Catholic contexts, there are two religious perspectives on suffering. On one hand, excessive suffering that blocks your goals is thought to be a sin. Simultaneously, suffering that allows you to stay engaged in your life is thought to bring you closer to God. It’s almost like broadcasting your suffering highlights you as a more complex and virtuous human being in other people’s eyes. Moreover, in India and Ecuador suffering can be interpreted as a rift in social networks that requires mending.
Should there be culture-specific approaches to depression?
We have evidence that public education efforts to teach people in non-western countries how to be properly depressed western-style result in changes in how people think about their distress. In Japan, for example, pharmaceutical companies once engaged in a systematic campaign to train people to recognize both major and minor depression as problems (“a cold of the soul”). I can imagine if somebody is suffering and finally there is a label, they might get treatment, which would be a positive outcome. I can also imagine people who have formerly obtained support and would have done well through the use of social networks and traditional mood regulation, are now thinking of themselves as sick. The older immigrants have a lot of cultural wisdom. Why do we assume that our knowledge is best for them, instead of learning from them and understanding how they cope? It’s a major direction for research for the next decades.
Are there genetic vulnerabilities for depression across cultures?
Genetic vulnerability differs substantially from country to country. East Asian contexts, for example, show a high prevalence of genes associated with depression. Yet, despite these vulnerabilities, they develop fewer cases of the disorder. One hypothesis is that genetic vulnerabilities have co-evolved with culture, creating extra protective factors (in this case, extra interdependence). However, when these people leave their cultural contexts, they have a higher risk of developing depression.
What factors protect against depression?
Social stability and functional relationships are big protective factors against depression. East Asian contexts promote stable social networks. For example, most adults in Japan are still in frequent contact with someone they have known since childhood. In countries like the U.S., that’s rarer because of high mobility levels. (Of course, it depends on the quality of the relationships: if you are stuck with people who create tensions for you, it can be problematic.) Another leading hypothesis is that some cultures reinforce ways of regulating emotions that may be more functional than others. Finally, by virtue of prioritizing emotions and personal happiness, in contexts like the U.S., we are creating a discrepancy between how we feel and how we are supposed to feel. This can lead to additional problems.
What is the role of emotion regulation?
Emotion regulation is increasingly becoming understood as a core factor in all affective disorders. In western societies, we don't see enough adaptive strategies like reappraisal: learning to tell yourself a different story that would eventually lead to different emotions. There is also not enough social regulation of emotion, which occurs by sharing our emotions with others. Research shows that cultures can facilitate functional regulation strategies. For example, Igor Grossmann’s work shows that Russians make rumination (generally considered a dysfunctional strategy) more functional by encouraging people to ruminate about the self from another person’s perspective, making rumination almost reappraisal-like in its quality.
How do symptoms of depression differ across cultures?
Best studied differences in expression of depression are whether symptoms are primarily experienced in the body, or as disorders of emotions and cognitions. In the U.S., we officially look for both, with an emphasis on affective features; you can’t be diagnosed with depression unless you have either depressed mood or anhedonia (lack of pleasure). On the other hand, research based on Chinese samples shows that people there are more likely to experience and express depression as bodily symptoms: the person is tired and not sleeping, they don't have energy and aren’t concentrating well. Historically, it’s the diagnosis of neurasthenia (weakness of the nerves), which migrated to China from Europe via the Soviet Union. Essentially, it’s major depression without the affective features.
How is depression assessed across cultures?
People don't seek help in the same manner, and help is not available in the same way. Moreover, the extent to which symptoms are recognized as pathology vs. an unpleasant but normative characteristic of life might differ. Assessment is a challenge in part because many of our assessment tools are based on the western set of criteria. Because of commonalities, we might catch some symptoms, but we might also miss presentations of the disorder that look different. We have started to develop tools that incorporate locally meaningful symptoms.
How do treatment methods differ across cultures?
Pharmaceutically, we know that prescriptions and doses need to be altered based on various factors, including ethnicity. There is accumulating data showing that some approaches that are effective in the U.S. (e.g., cognitive-behavioral therapy) are also looking promising in other cultures. Similarly, mindfulness approaches from the East have been found to be effective in western samples. We have this idea of therapy as individual-based, yet we know from research that having somebody next to you, even if you don't discuss your problems, is regulatory. Thus, approaches that make use of social ties have a lot of promise, particularly outside highly individualistic contexts. I’m hoping that this gap in clinical science will get increasingly filled and we will enrich our toolset of approaches for treating depression.
Many thanks to Yulia Chentsova-Dutton for being generous with her time and insights. Dr. Chentsova-Dutton is an Associate Professor of Psychology at Georgetown University and the head of the Culture and Emotions lab.
Marianna Pogosyan, Ph.D., is an intercultural consultant specializing in the psychology of cross-cultural transitions.
Fertility Preferences and Cognition: Religiosity and Experimental Effects of Decision Context on College Women
Marshall, E. A. and Shepherd, H. (2017), Fertility Preferences and Cognition: Religiosity and Experimental Effects of Decision Context on College Women. Fam Relat. doi:10.1111/jomf.12449
Abstract: Better models of culture and cognition may help researchers understand fertility and family formation. The authors examine cognition about fertility using an experimental survey design to investigate how fertility preferences of college women are affected by two prompts that bring to mind fertility-relevant factors: career aspirations and financial limitations. The authors test the effects of these prompts on fertility preferences and ask how effects vary with respondent religiosity, an aspect of social identity related to fertility preferences. The authors find significant effects of treatment on fertility preferences when accounting for religiosity: Less religious women who considered their career aspirations or financial limitations reported smaller desired family size, but this effect was attenuated for more religious women. This study demonstrates how fertility preferences are shaped by decision contexts for some sociodemographic groups. The authors discuss how the findings support a social–cognitive model of fertility.
Abstract: Better models of culture and cognition may help researchers understand fertility and family formation. The authors examine cognition about fertility using an experimental survey design to investigate how fertility preferences of college women are affected by two prompts that bring to mind fertility-relevant factors: career aspirations and financial limitations. The authors test the effects of these prompts on fertility preferences and ask how effects vary with respondent religiosity, an aspect of social identity related to fertility preferences. The authors find significant effects of treatment on fertility preferences when accounting for religiosity: Less religious women who considered their career aspirations or financial limitations reported smaller desired family size, but this effect was attenuated for more religious women. This study demonstrates how fertility preferences are shaped by decision contexts for some sociodemographic groups. The authors discuss how the findings support a social–cognitive model of fertility.
The role of endocannabinoids is to maintain an exquisite balance of neurotransmitter levels, on one hand preventing excessive release & potential excitotoxicity while on the other hand ensuring adequate levels for optimal signaling
From “Azalla” to Anandamide: Distilling the Therapeutic Potential of Cannabinoids. Rajiv Radhakrishnan, David A. Ross. Biological Psychiatry, Volume 83, Issue 2, 15 January 2018, Pages e27–e29. https://doi.org/10.1016/j.biopsych.2017.11.017. Refers to Functional Redundancy Between Canonical Endocannabinoid Signaling Systems in the Modulation of Anxiety, by Gaurav Bedse, Nolan D. Hartley, Emily Neale, Andrew D. Gaulden, Toni A. Patrick, Philip J. Kingsley, Md. Jashim Uddin, Niels Plath, Lawrence J. Marnett, Sachin Patel. Biological Psychiatry, Volume 82, Issue 7, 1 October 2017, Pages 488-499
Rolf Dagen's commentary: The brain's natural marihuana hold a key position in the brain, commanding different unique channels, keeping the system in the so-called Goldilocks zone. https://twitter.com/DegenRolf/status/940099167468208129
---
What has emerged from these initial discoveries is one of the most fascinating stories in modern neuroscience: as it turns out, the endocannabinoid system is a unique regulatory neurotransmitter system, defying many properties of conventional neurotransmitters (6). First, unlike other neurotransmitters (e.g., serotonin, dopamine, acetylcholine), endocannabinoids are not stored in vesicles—rather, they are synthesized on demand. A second fascinating detail is that they are produced and released from the postsynaptic terminal (generally in response to the activation of other receptors, such as metabotropic glutamate receptor 1 or metabotropic glutamate receptor 5). Once released, they then diffuse into the synaptic cleft and act on the cannabinoid receptor on the presynaptic terminal to inhibit the further release of neurotransmitters (Figure 1). This process is known as retrograde signaling: a signal sent from the postsynaptic terminal to the presynaptic terminal, in this case acting as an inhibitory “brake” on the action of the neurotransmitter.
Retrograde signaling has been noted for only a few other neurotransmitters (e.g., nitric oxide and dynorphin). A third unique aspect of endocannabinoids is that they exhibit a property known as the entourage effect: their activity can be enhanced by structurally related, but otherwise biologically inactive, endogenous constituents [a property shared by other lipid mediators (7)]. A final property of the endocannabinoid system that is worth highlighting is that activation of the CB1R can have biphasic effects, which is to say that different levels of stimulation can lead to opposite types of outcomes. For example, low-dose stimulation of CB1R can have an anxiolytic effect, whereas high-dose stimulation may be ineffective or even anxiogenic.
The role of endocannabinoids is thus to maintain an exquisite balance of neurotransmitter levels, on one hand preventing excessive release and potential excitotoxicity while on the other hand ensuring adequate levels for optimal signaling. Effectively, they help keep neurotransmitter levels in the synapse in the so-called Goldilocks zone where the balance is “just right.” It is therefore not surprising that the endocannabinoid system is emerging as a significant player in the modulation of many physiological processes, ranging from pain sensation and autonomic system tone to the regulation of intrauterine development, appetite, mood, cognition, and anxiety. Given this wide role across physiological functions, it is not surprising that therapeutic uses have begun emerging for a range of medical conditions.
Rolf Dagen's commentary: The brain's natural marihuana hold a key position in the brain, commanding different unique channels, keeping the system in the so-called Goldilocks zone. https://twitter.com/DegenRolf/status/940099167468208129
---
What has emerged from these initial discoveries is one of the most fascinating stories in modern neuroscience: as it turns out, the endocannabinoid system is a unique regulatory neurotransmitter system, defying many properties of conventional neurotransmitters (6). First, unlike other neurotransmitters (e.g., serotonin, dopamine, acetylcholine), endocannabinoids are not stored in vesicles—rather, they are synthesized on demand. A second fascinating detail is that they are produced and released from the postsynaptic terminal (generally in response to the activation of other receptors, such as metabotropic glutamate receptor 1 or metabotropic glutamate receptor 5). Once released, they then diffuse into the synaptic cleft and act on the cannabinoid receptor on the presynaptic terminal to inhibit the further release of neurotransmitters (Figure 1). This process is known as retrograde signaling: a signal sent from the postsynaptic terminal to the presynaptic terminal, in this case acting as an inhibitory “brake” on the action of the neurotransmitter.
Retrograde signaling has been noted for only a few other neurotransmitters (e.g., nitric oxide and dynorphin). A third unique aspect of endocannabinoids is that they exhibit a property known as the entourage effect: their activity can be enhanced by structurally related, but otherwise biologically inactive, endogenous constituents [a property shared by other lipid mediators (7)]. A final property of the endocannabinoid system that is worth highlighting is that activation of the CB1R can have biphasic effects, which is to say that different levels of stimulation can lead to opposite types of outcomes. For example, low-dose stimulation of CB1R can have an anxiolytic effect, whereas high-dose stimulation may be ineffective or even anxiogenic.
The role of endocannabinoids is thus to maintain an exquisite balance of neurotransmitter levels, on one hand preventing excessive release and potential excitotoxicity while on the other hand ensuring adequate levels for optimal signaling. Effectively, they help keep neurotransmitter levels in the synapse in the so-called Goldilocks zone where the balance is “just right.” It is therefore not surprising that the endocannabinoid system is emerging as a significant player in the modulation of many physiological processes, ranging from pain sensation and autonomic system tone to the regulation of intrauterine development, appetite, mood, cognition, and anxiety. Given this wide role across physiological functions, it is not surprising that therapeutic uses have begun emerging for a range of medical conditions.
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