title: Location and conduction velocity of raphespinal neurones in nucleus raphe magnus and raphe pallidus in the cat.
abstract: Extracellular recordings were made from raphespinal neurones identified by antidromic stimulation of their axons in the upper lumbar cord. Conduction velocities ranged from 1.25 to 67 m/sec. Neurones with axonal conduction velocities of 1.25-5 m/sec were found mainly ventrally, in nucleus raphe pallidus; many of these are presumably tryptaminergic cells with unmyelinated axons. In nucleus raphe magnus most raphespinal neurones had axonal velocities between 7 and 67 m/sec; these axons must be myelinated. This indicates that most raphespinal neurones in nucleus raphe magnus are non-tryptaminergic, and it is suggested that analgesia mediated by raphespinal neurones may not be solely due to the action of 5-hydroxytryptamine descending systems.
authors: Department of Physiology, Medical School, University of Birmingham, Birmingham B15 2TJ Great Britain.
authors: D C
authors: DC
authors: West
authors: J H
authors: JH
authors: Wolstencroft