Effects of vasopressin on portal-systemic collaterals of cirrhotic rats.
OBJECTIVE
Arginine vasopressin (AVP) exerts a constrictive effect on the portal-systemic collaterals of non-cirrhotic portal hypertensive rats, but its effect on cirrhotic rats is unknown. The aim of this study was to investigate the response of AVP and the modulatory roles of nitric oxide and prostaglandin on collaterals of common bile duct-ligated (BDL) cirrhotic rats.


METHODS
The collateral vascular responsiveness to graded concentrations of AVP (10(-10) - 3 x 10(-7) M) was tested by an in situ collateral perfusion system pretreated with Nomega-nitro-L-arginine (L-NNA, 100 microM), indomethacin (INDO, 10 microM), or both. The collateral responses to AVP with the pretreatment of a vasopressin V1 receptor antagonist d(CH2)5Tyr(Me) arginine vasopressin or a V2 receptor agonist 1-desamino-8-D-arginine vasopressin (DDAVP, 10(-10) - 3 x 10(-7) M) were also evaluated.


RESULTS
The perfusion pressure of collaterals was significantly increased by AVP, and this effect was inhibited by the addition of the V1 receptor antagonist. DDAVP had no effect on the collaterals. Incubation with L-NNA or L-NNA plus INDO, but not INDO alone, significantly potentiated the constrictive effects of AVP. The constrictive effect of AVP in the combination group was similar to that in the L-NNA alone group.


CONCLUSIONS
The results show that AVP produces a direct vasoconstrictive effect on the portal-systemic collaterals of BDL cirrhotic rats. The constrictive effect of AVP is mediated by the vasopressin V1, instead of V2, receptors. Nitric oxide may play a more important role than prostaglandin in modulating the collateral vascular response to AVP in BDL cirrhotic rats.
Chan
Che-Chang
CC
Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taiwan, Republic of China.
Wang
Sun-Sang
SS
Lee
Fa-Yauh
FY
Chang
Full-Young
FY
Lin
Han-Chieh
HC
Hou
Ming-Chieh
MC
Huang
Hui-Chun
HC
Lee
Shou-Dong
SD
D000818:Animals; D003097:Collateral Circulation / Q000187:drug effects* / Q000502:physiology; D004195:Disease Models, Animal; D008102:Liver Circulation / Q000187:drug effects; D008103:Liver Cirrhosis / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D011168:Portal System / Q000187:drug effects* / Q000502:physiology; D011336:Probability; D011453:Prostaglandins / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity; D014667:Vasopressins / Q000494:pharmacology*
D011453:Prostaglandins; D014667:Vasopressins; D009569:Nitric Oxide