Alpha-adrenergic receptors in the hepatic sinusoid of the rat and its relation to portal pressure

Abstract

The presence of alpha-adrenergic receptors in the hepatic sinusoid of the rat, and its relation to portal pressure (PP), by local and systemic infusion of bolus doses of norepinephrine (NE) (1 microgram/100 g) and phentolamine (FA) (25 micrograms/100 g) have been studied.Fifty-five male Wistar rats with intact nerves have been used in 5 experiments.When NE is injected into the portal vein (PV), it provokes an immediate rise in PP, modified subsequently by the systemic effect is induced earlier and more intensely than if injected into PV.If FA is infused into PV, PP decreases and the effect of posterior infusion of NE is less marked.These results suggest the presence of alpha-adrenergic receptors in the hepatic sinusoid of the rat.When they are stimulated PP raises, indicating that basal PP is maintained not only because of hepatic arterial flow, but also through a distinct sympathetic tone.