[Changes in background activity of periaqueductal gray neurons through application of serotonin or inhibition of its synthesis].

Abstract

Application of serotonin (ST, 1.10(-4) M to periaqueductal grey neurons influenced background activity (BA) only in the third group of cells. In 45.5% of them ST evoked depression of BA. Through application of ST remarkable potentiation of BA inhibition evoked by locus coeruleus (LC), substantia nigra (SN) stimulation was found, but inhibitory affects of nucleus raphe magnus (NRM) were less intensive. After intraperitoneal injection of p-chlorophenylalanine the efficiency of NRM stimulation became lower, but influences of LC and SN on BA increased. The mechanisms of serotoninergic effects on BA of periaqueductal grey neurons are discussed.