In our bi-weekly Journal Club, soon-to-be Master Phillip Long presented an article on seasonal variation in ER alpha dimorphism in green anole. Estradiol (E2) binds to ER-alpha or estrogen receptor-alpha to mediate male reproductive behaviors and female receptive (i.e. give it to me, baby) sexual behaviors. E2 is also responsible for brain masculination. Imagine how this information could change current and past male-female societal expectations! Anyways, back to science. In the paper discussed, male and female anoles were captured during their breeding and non-breeding seasons (May and October, respectively) and brought into the lab to assess ER-alpha expression in various brain regions. Regions of high ER-alpha expression include the ventromedial hypothalamus, medial preoptic area, and the ventromedial amygdala. This is no surprise give that these brain areas mediate sexual dimorphism of the brain and behavior. Other areas with marked ER-alpha expression include the septum which mediates aggression (is this the neurobiological etiology of S&M?!), the suprachiasmatic nucleus which I imagine regulates seasonal breeding, and the nucleus accumbens which mediates reward (again, again!).
Though there were many questionable methodologies within the paper, which led me to believe it was an undergraduate research project (no offense), it certainly is interesting to find differential expression of ER-alpha in a reptilian model that is comparable to ER-alpha expression in mammalian and avian models. Neuroscience rocks.
Below is a video of a male green anole courting a female. When anoles court, they distended their dulap (vibrant bright orange pouch below their jaw) and bob their head. I had the opportunity to see this while wandering around the Costa Rican cloud forests. It’s awesome.