ADRENERGIC INFLUENCE ON BILE SECRETION - AN EXPERIMENTAL-STUDY IN THE CAT

The influence on bile secretion of electrical stimulation of the splanchnic nerves and arterial infusion of adrenergic agonists was studied in anaesthetized cats. The bile salt secretion was supported by a continuous intravenous infusion of sodium glycocholate. Electrical stimulation of the splanchnic nerves reduced the volume outflow of bile from 0.71 to 0.44 ml h-1 kg-1 body wt and raised the bile acid concentration in bile, while the bile salt secretion rate was not affected. This response was reduced but not blocked by pretreatment with phentolamine, an α-adrenergic blocker, at a dose that prevented the blood pressure response. Infusion of noradrenaline, a mainly α-adrenergic agonist, into the hepatic artery mimicked the response. Infusion of isoprenaline, a β-adrenergic agonist, also reduced the volume outflow of bile from the liver. The biliary clearances of mannitol and polyethylene glycol 900, both of which are suggested to reflect canalicular events, were reduced by stimulation of the splanchnic nerves and infusion of noradrenaline. It is concluded that stimulation of the α-adrenergic receptors reduces the bile acid-independent bile secretion. This reduction in bile flow induced by stimulation of the splanchnic nerves and infusion of noradrenaline is elicited mainly at the canalicular level.