Meeting Abstract
One of the long-term goals of my research program is to identify and characterize the multiple rapid effects of steroid hormones on the neurons and neural circuits that have behavioral relevance. We are pursuing the following questions: (1) How do hormones impact neurons on different timescales to affect the selection of context-appropriate behaviors? and (2) How do small ephemeral signaling molecules, endocannabinoids, behave as a switch upon which hormones act? We are using a combination of in vivo single-unit and slice whole cell electrophysiology, behavior, and imaging to investigate these questions in the clasp-controlling region of the hindbrain of an amphibian, Rough-skinned newts. Our results have begun to elucidate two novel mechanisms in which the steroid hormone corticosterone (CORT) mediates rapid and non-genomic behavioral changes. The first is by modulating intrinsic and synaptic electrical properties of clasp-controlling neurons. We know that endocannabinoids block CORTs ability to suppress clasping behavior, and we are currently investigating how endocannabinoids are involved at the level of neural signaling. Secondly, CORT blocks receptor-mediated endocytosis of vasotocin; acting non-genomically and rapidly but for a finite length of time (~30-45 min), effectively silencing the typically pro-courtship effect of vasotocin in a behaviorally relevant manner. These findings are consistent with our working hypothesis that CORT employs disparate cellular mechanisms in a cascade that functions within a rapid time frame of ms to min. This cascade being critical for context-appropriate behavioral responses to occur because neurons respond differently to specific temporal input patterns, and must allow for flexible behavioral selection processes.
