Effects of propranolol on intestinal microcirculation of normal and portal hypertensive rats

doi:10.1016/0168-8278(95)80223-1

Journal of Hepatology

Volume 22, Issue 6, June 1995, Pages 677-684

https://doi.org/10.1016/0168-8278(95)80223-1 Get rights and content

Abstract

Background/Aims: The goal of the present study was to compare the efficacy of locally and systemically administered propranolol in normal and prehepatic portal hypertensive rats, and to test the hypothesis that β-adrenoceptor blockade reduces intestinal arteriolar diameter by allowing unopposed a-adrenergic activity.

Methods: The small intestine was prepared for in vivo microcirculatory studies and transferred to an intravital microscope where arteriolar diameter and erythrocyte velocity were continuously monitored. First order arteriolar (1A) blood flow was calculated from the product of mean velocity and microvessel cross-sectional area. In separate experiments, diameter responses of 2A and 3A were monitored. Once steady-state conditions were achieved, the preparation was challenged by topically applied doses of propranolol (0.01–100.00 μM) in the presence and absence of the alpha-receptor antagonist, phentolamine. In a separate group of experiments, the effects of systematically administered propranolol (10 mg/kg body weight) were evaluated before and after local alpha-adrenoceptor blockade.

Results: Propranolol produced significant vasoconstriction and decreased blood flow in both normal and portal hypertensive rats. Portal hypertensive arterioles exhibited an attenuated response to propranolol. Local administration of phentolamine completely blocked the propanolol-induced diameter changes. Comparison of equivalent concentrations of local and systemic propranolol indicated that both routes of administration were equally effective.

Conclusion: The results of the present study suggest that the cardiovascular actions of propranolol are predominantly mediated through blockade of peripheral β₂-adrenoceptor.

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Effects of propranolol on intestinal microcirculation of normal and portal hypertensive rats

Abstract

Gastroenterology

Gastroenterology

J Hepatol

Gastroenterology

Gastroenterology

Gastroenterology

Microvasc Res

Microvasc Res

Microvasc Res

Propranolol in the prevention of first upper gastrointestinal tract hemorrhage in patients with cirrhosis of the liver and esophageal varices

N Engl J Med

Propranolol in the prevention of the first hemorrhage from esophagogastric varices: a multiple, randomized clinical trial

Hepatology

A randomized controlled study of propranolol for prevention of recurrent gastrointestinal bleeding in patients with cirrhosis: a final report

Hepatology

β-Blockade prevents recurrent gastrointestinal bleeding in well-compensated patients with alcoholic cirrhosis: a multicenter randomized controlled trial

Hepatology