Cannabis and Gender Development
A recent study has shown that there is a correlation between cannabinoid intake and masculine hormone-based behavior. The study was conducted using a cannabinoid-mimicking drug rather than actual cannabis, and only involved rats, not humans. However, this mirrors a larger trend in cannabinoid studies happening in academia, and this specific study has interesting implications for understanding gender hormones and hormone-typical behavior in relation to cannabis use.
This study is titled “Sex difference in cell proliferation in developing rat amygdala mediated by endocannabinoids has implications for social behavior.” The research was conducted by Desiree Krebs-Kraft from the University of Maryland, and she, along with her team, looked at the effects of a cannabinoid-mimicking drug on newly born male and female rats. Kraft published her findings in the Proceedings of the National Academy of Sciences of the United States of America (PNAS). The findings show that early exposure to cannabinoids in young female rats caused more male-typical behavior than that of females who were not exposed (Krebs-Kraft et. al, 2010).
Although this study is groundbreaking due to the fact that it is looking at male and female hormone-based behavior and cannabinoids, this study follows a trend of cannabinoid research using rats in order to learn more about the effects of cannabis on living creatures. A 2012 study titled “Short- and Long-Term Cognitive Effects of Chronic Cannabinoids Administration in Late-Adolescence Rats” and conducted by Hila Abush and Irit Akirav, looked at the effects of cannabis on cognition and memory using a similar procedure. Their study showed that some forms of short-term memory loss are effected by lack of cannabinoids, while others are probably dependent on cannabinoid residue (Abush & Akirav, 2012).
Similarly, Dr. Masahiro Matsunaga and his team of researchers at the Department of Health and Psychosocial Medicine at the Aichi Medical University School of Medicine in Japan conducted a study called “Genetic Variations in the Human Cannabinoid Receptor Gene Are Associated with Happiness.” Their study revealed that the cannabinoid receptor gene is associated with both positive emotional stimuli and subjective happiness. While many of these studies use cannabinoid-mimicking substances due to the cannabis law, much is still being learned about cannabinoid effects on the brain from these studies on lab rats (Matsunaga, et. al, 2014).
All of these studies yielded very interesting results regarding cannabinoids and their effects, but what is so interesting about the Krebs-Kraft study is that it specifically looks at how cannabis influences gender development. As the brain is developing, there are many chemicals in the body that can change neural pathways and alter brain and gender development. Endocannabinoids are already found naturally in the brain, and while research is still being done on the topic, they appear to influence gender-specific behaviors (Krebs-Kraft, 2010).
During her study, Krebs-Kraft and her team looked at the non-neuron brain cells (dividing MeA glia) in the medial amygdala of four-day-old rats. She noticed that female rats had more non-neuron brain cells than male rats, but when a drug that mimicked endocannabinoids was introduced to the young rats, the female rats’ rate of non-neuron brain cells more closely mimicked that of the males. Krebs-Kraft also observed that behavior in female rats changed when given the endocannabinoids. They became more playful and frolicked more, which more closely mirrored the behavior of the male rats. The male rats, on the other hand, did not experience a surge in non-neuron brain cells (Krebs-Kraft, 2010).
“Our results show that endocannabinoids are part of a natural signaling system that underlies the establishment of sex differences in the brain that are an important part of social behavior,” Margaret McCarthy, who co-authored the study, recently told Scientific American. “This would suggest that the use of cannabis during pregnancy could alter those systems and have unintended consequences.”
The implications of this study speak to the larger arena of cannabinoid and brain development research, and could uncover new things about the plant. “These are the kind of findings that will enable us to argue for future research, because this is the kind of data that we need that might uncover important attributes of the plant that might have clinical relevance, that might actually help,” explained Sue Sisley, MD, a practicing physician of Internal Medicine and Psychiatry in Scottsdale, Arizona. “Some of the research we do is so esoteric, that to many, it doesn’t even seem to have any relevance to daily human life, but you never know. In this case, this is the kind of thing that could open up whole new areas of research. This could open the door to a whole new study. Overall, because we still know so little about cannabinoids and cannabis, I’d say this points to how desperately research on these things is needed in this country.”
Cannabinoid research has come a long way since regulations have begun to loosen, but as Sisley points out, there is still so much to learn. Many of these studies still only use substances that mimic the endocannabinoids in actual cannabis, since testing on the real thing is not allowed. If the next few years actually see follow-through with rescheduling cannabis, even more strides can be taken to understand the complex relationship between cannabinoids and brain development.
Works Cited:
Abish, Hila & Akirav, Irit. (2012). “Short- and Long-Term Cognitive Effects of Chronic Cannabinoids Administration in Late-Adolescence Rats.” Retrieved from: http://dx.doi.org/10.1371/journal.pone.0031731
Krebs-Kraft, D., Hill, M., Hillard, C., & McCarthy, M. (2010). “Sex difference in cell proliferation in developing rat amygdala mediated by endocannabinoids has implications for social behavior.” Retrieved from: http://www.pnas.org/content/107/47/20535.full?sid=267d685a-a8e3-45f7-a1b0-82a3361ffef3
Matsunaga, M., Isowa, T., Yamakawa, K., Fukuyama, S., Shinoda, J., Yamada, J., & Ohira, H. (2014). “Genetic Variations in the Human Cannabinoid Receptor Gene Are Associated with Happiness.” Retrieved from: http://dx.doi.org/10.1371/journal.pone.0093771
