Effect of blood pressure on A2 noradrenergic neurons

Single-unit recordings of A2 noradrenergic neurons were obtained in urethane-anesthetized rats. Norepinephrine-induced elevations in arterial pressure produced small decreases in the discharge rate of the cells; this effect was not observed in animals with bilateral sections of the ninth and tenth nerves. The activity of A2 cells was neither pulse-synchronous at high levels of arterial pressure nor significantly affected by carotid stretch. It is concluded that these neurons do not receive a significant baroreceptor input.