Chapter 15 Brain vasopressin: from electrophysiological effects to neurophysiological function

Abstract

This chapter discusses the electrophysiological effects and the neurophysiological function of brain vasopressin (VP). The two different actions of VP on lateral septum (LS) and ventral hippocampus (VH) neurons in vivo and in vitro are discussed. One of the actions, the excitation of LS and VH neurons, resembles the action of glutamate (GLU) and other excitatory amino acids (EAA). The VP-induced excitation involves EAA receptors and can be a pharmacological effect of the peptide. The other action of VP on LS and VH neurons is to temporarily increase the responses of neurons to exogenous and synaptically released EAAs. This VP action, observed in the majority of the LS and VH neurons in vivo, can last for many minutes following termination of peptide administration. A significant increase in EAA transmission on LS neurons in vitro is obtained with peptide. It is thus conceivable that the EAA transmission-enhancing action of VP is a physiological action of the peptide, related to the function of the brain VP system in the LS and hippocampus, and in other brain structures innervated by this system.