Hemodynamic effects of terbutaline, a beta 2-adrenoceptor agonist, in conscious rats with secondary biliary cirrhosis.
The hemodynamic responses to terbutaline - a selective beta 2-adrenoceptor agonist - were studied in conscious normal rats and in conscious rats with secondary biliary cirrhosis. Compared with those of normal rats, dose-response curves in cirrhotic rats indicated significantly decreased reactivity in arterial pressure and heart rate. Half-maximal effective dose was not significantly different between the two groups. Terbutaline induced significant, dose-dependent decreases in portal pressure in both normal rats (9.3%) and cirrhotic rats (13.8%). In normal rats, terbutaline administration (32 micrograms.min-1.kg-1 body wt) increased both cardiac output and portal tributary blood flow, thus mimicking hemodynamic changes in cirrhotic rats. In cirrhotic rats, despite a significant increase in portal tributary blood flow (from 19.9 +/- 1.7 ml/min to 22.7 +/- 1.5 ml/min), terbutaline decreased portal pressure from 17.4 +/- 1.0 mm Hg to 15.0 +/- 0.8 mm Hg. This study indicates that increased beta 2-adrenoceptor stimulation in cirrhotic rats may be involved in hyperdynamic circulation. The association of a decreased portal pressure and increased splanchnic blood flow suggests that beta 2-adrenoceptor stimulation may modulate hepatic and portal collateral vascular resistance.
Unité de Recherches de Physiopathologie Hépatique (INSERM U-24), Hôpital Beaujon, Clichy, France.
J L
JL
Poo
A
A
Braillon
A
A
Hadengue
C
C
Gaudin
D
D
Lebrec
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D008105:Liver Cirrhosis, Biliary / Q000503:physiopathology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013726:Terbutaline / Q000494:pharmacology*
D000318:Adrenergic beta-Agonists; D013726:Terbutaline