Selective alteration of agonist-mediated contraction in hepatic arteries isolated from patients with cirrhosis.
BACKGROUND & AIMS: Impaired pressor function in cirrhosis may be specific to certain agonists and vascular territories. This investigation determined whether responses to arginine vasopressin ( AVP) and 5-hydroxytryptamine (5-HT) were impaired in hepatic arteries from cirrhotic patients. METHODS: Cumulative concentration-response curves were produced for AVP (10(-11) to 3 x 10(-6) mol/L), 5-HT (10(-9) to 3 x 10(-5) mol/L), and potassium chloride (2.5 -120 mmol/L) in hepatic arteries from liver donors (noncirrhotic) and recipients (cirrhotic). The receptor stimulated by AVP was identified using a V(1)-receptor antagonist (d[CH(2)](5)Tyr[Me]AVP) and a selective V(2)-receptor agonist (desmopressin [DDAVP]). RESULTS: Cirrhotic patients had a high heart rate (98 +/- 4 beats/min) and cardiac output (9.87 +/- 0.51 L/min) but low peripheral vascular resistance (711 +/- 35 dyn. s/cm(5)). None of the arteries had a functional endothelium. Maximal contraction (but not sensitivity) to AVP was smaller (P = 0.0002) in hepatic arteries from recipients (34.03% +/- 3.42% KCl) than donors (60.69% +/- 5.56% KCl). 5-HT-mediated contraction was enhanced in recipient hepatic arteries (88.81% +/- 5.43% KCl vs. 71.63% +/- 4. 46% KCl; P = 0.01), but sensitivities were similar (P = 0.20). KCl-mediated contractions were similar (P = 0.87) in both groups. Arteries did not respond to DDAVP, but d(CH(2))(5)Tyr(Me)AVP produced a concentration-dependent rightward shift in the response to AVP. CONCLUSIONS: These results demonstrate a selective impairment of V(1) receptor-mediated contraction in denuded hepatic arteries from cirrhotic patients, suggesting an abnormality within the vascular smooth muscle.[1]References
- Selective alteration of agonist-mediated contraction in hepatic arteries isolated from patients with cirrhosis. Islam, M.Z., Williams, B.C., Madhavan, K.K., Hayes, P.C., Hadoke, P.W. Gastroenterology (2000) [Pubmed]
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