Regulation of Autonomic Cardiovascular Function by the Rostral Ventromedial Medulla

Abstract

It is generally accepted that neural elements in the rostral ventral medulla (RVM) are essential for the neurogenic maintenance of arterial pressure. In recent years, the source of vasomotor tone in RVM has been ascribed to a small region in the lateral RVM lying just caudal to the posterior pole of the facial nucleus. This region, referred to as the rostral ventrolateral medulla (RVLM), contains a group of bulbospinal neurons responsible for the maintenance of sympathetic vasomotor tone in a variety of species (Barman and Gebber, 1985; Brown and Guyenet, 1985; Morrison et al., 1988; Ross et al., 1984a). These neurons are also reported to play significant roles in a number of cardiovascular and somatosympathetic reflex responses (Dampney and Moon, 1980; Granata et al., 1985; Morrison and Reis, 1989). Recent evidence suggests that the rostral medulla contains other subregions involved in the maintenance of neurogenic vasomotor tone, which also play unique roles in the tonic and reflex regulation of cardiovascular function.