Vasopressin receptor expression in Anolis carolinesis relative to season (breeding vs. nonbreeding) and sex (male vs. female)

Abstract

The social behavior neural network contains a variety of signaling neuropeptides, such as vasopressin (VP), and their receptors. Previous studies in rodents and songbirds have demonstrated that there are differences in neural vasopressin receptor (VPR) expression based on sex (male vs. female) and season (breeding vs. non-breeding). VPRs are G protein-coupled receptors consisting of several subtypes. The V1aR and V1bR subtypes are the most well-known mediators of the effects of VP on social behavior. Understanding differences in receptor expression can help us understand behavioral differences across sexes and seasons. Using green anoles (Anolis carolinesis), 10 breeding season animals (6 males and 4 females) and 12 nonbreeding season animals (6 males and 6 females) were compared for amount of V1aR expression across pertinent brain regions. Using autoradiography, we analyzed the amount of V1aR by overlaying photomicrographs of Nissl-stained brain sections over the autoradiography slides in Photoshop, and then outlined target brain regions. Average pixel brightness was determined as a measure of V1aR expression for each area. Based on previous research, we predict that breeding males will have generally higher V1aR expression than females and non-breeding males. We also predict no difference in V1aR expression among females between seasons.