Departments of Psychology and Pharmacology and the Cardiovascular Center, University of Iowa, Iowa City, IA 52242, USA
Abstract:
The effects of intracarotid infusions of the peptide gamma2-melanocyte stimulating hormone (γ2-MSH) on electrophysiologically and immunohistochemically identified supraoptic nucleus (SON) units were investigated Over a wide dose range this agent always excited SON units, while control infusions of vehicle had no effect. Because neural responses invariably preceded blood pressure elevation, it appears that γ2-MSH excitation of the magnocellular system was due to a direct effect on the central nervous system and was not a result of systemic cardiovascular responses. These results suggest a forebrain γ2-MSH sensitive site in the activation of SON magnocellular neurons.