PHYSIOLOGICAL-ASPECTS OF AUTONOMIC NERVOUS-SYSTEM FUNCTION

Investigations continue into the central neuronal circuitry involved i n cardiovascular control, the activity of sympathetic efferents, cardi ovascular responses, and experimental hypertension. Neurons within the ventrolateral medulla are integral to several reflex pathways. The ac tivation of neurons within the A5 cell group can generate complex patt erns of sympathetic and cardiovascular response. The type of respirato ry modulation of a sympathetic neuron may be associated with its funct ion. Opioid mechanisms within the central nervous system are important in cardiovascular responses to hemorrhage. The central actions of ang iotensin II and atrial natriuretic peptide may blunt the baroreceptor reflex in spontaneously hypertensive rats.