Colocalization of receptors for vasoactive peptides on astrocytes of cultured rat spinal cord and brain stem: electrophysiological effects of atrial and brain natriuretic peptide, neuropeptide Y and bradykinin

Abstract

Electrophysiological studies have been made of the actions of the vasoactive peptides atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), neuropeptide Y (NPY) and bradykinin (BK) on astrocytes in explant cultures of rat brain stem and spinal cord. Addition of ANP, BNP and NPY to the bathing solution at concentrations of 10 −8 and 10 −7 M caused depolarizations of the majority of astrocytes studied, some cells were hyperpolarized and on a small number of cells the peptides had no action. BK (10 −8 M) only induced depolarizations of almost all astrocytes studied. Our electrophysiological data provide strong evidence for the presence of receptors for these vasoactive peptides on astrocytes. When ANP, BNP, NPY and BK were tested on the same cell, all peptides were effective, suggesting a coexistence of peptidergic receptors on astrocytes.