Increased circulating vasopressin may account for ethanol-induced hypertension in rats.
BACKGROUND
Long-term ethanol intake has been reported to evoke both hypertension and increase of systemic vasopressin levels in rats.


METHODS
In this work, we investigated the involvement of systemic vasopressin in the hypertension evoked in rats by long-term ethanol (20% vol/vol) intake for 2 weeks, by systemic treatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP (50 microg/kg). Moreover, plasma arginine-vasopressin (AVP) content was quantified using an AVP radioimmunoassay and the expression of vasopressin mRNA in the supraoptic (SON) and paraventricular (PVN) nuclei was measured using real-time PCR.


RESULTS
Mild hypertension was observed after 2 weeks of ethanol treatment when compared with control animals. Moreover, an increase in both the expression of vasopressin mRNA and the vasopressin blood content was observed in ethanol-treated rats in comparison to the control group. Basal blood pressure levels of ethanol-treated animals were significantly reduced by IV treatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP. However, dTyr(CH2)5(Me)AVP had no effect on the blood pressure of control animals.


CONCLUSIONS
The results indicate that mild hypertension is already observed at an early phase of ethanol consumption in rats. Because the content of circulating vasopressin was increased in ethanol-treated rats and their basal blood pressure returned to control levels after IV treatment with a V1-vasopressin receptor antagonist, it is proposed that increased circulating vasopressin content may mediate the hypertension observed in ethanol-treated rats.
Resstel
Leonardo B M
LB
Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. leoresstel@yahoo.com.br
Scopinho
América A
AA
Lopes da Silva
Andréia
A
Antunes-Rodrigues
José
J
Rodrigues
José A
JA
Corrêa
Fernando M A
FM
D000428:Alcohol Drinking / Q000009:adverse effects* / Q000378:metabolism; D000818:Animals; D001127:Arginine Vasopressin / Q000037:antagonists & inhibitors / Q000097:blood* / Q000235:genetics; D001794:Blood Pressure / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000633:toxicity*; D000431:Ethanol / Q000633:toxicity*; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced* / Q000378:metabolism*; D008297:Male; D010456:Peptides, Cyclic / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014443:Tyrosine / Q000031:analogs & derivatives / Q000494:pharmacology
D002492:Central Nervous System Depressants; D010456:Peptides, Cyclic; D012333:RNA, Messenger; C433483:Tyr(Me)-AVP; D001127:Arginine Vasopressin; D000431:Ethanol; D014443:Tyrosine