Ethanol microinjection into the area postrema selectively attenuates baroreflex sensitivity measured by vasopressin in conscious rats.
Microinjection of ethanol (10 microg) into the area postrema (AP) of conscious rats attenuated baroreflex sensitivity (BRS) measured by arginine vasopressin (AVP) (-1.73 +/- 0.13 versus -2.47 +/- 0.16 bpm/mmHg), but not by phenylephrine (PE) (-1.94 +/- 0.26 versus -1.82 +/- 0.20 bpm/mmHg). Intra-AP injection of the V1 receptor antagonist D(CH2)5Tyr(Me)AVP replicated the differential effects of ethanol on BRS measured by AVP (-1.89 +/- 0.11 versus -2.52 +/- 0.10 bpm/mmHg) and PE (-2.10 +/- 0.12 versus -2.09 +/- 0.19 bpm/mmHg). Intra-AP artificial cerebrospinal fluid (ACSF) did not change BRS measured by AVP or PE. These data suggest that ethanol attenuates the facilitatory action of AVP on baroreflexes via its interaction with AVP neurons in the AP.
Mao
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Department of Pharmacology, School of Medicine, East Carolina University, Greenville, NC 27858-4353, USA.
Abdel-Rahman
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AA
D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000494:pharmacology; D017704:Baroreflex / Q000187:drug effects* / Q000502:physiology; D001933:Brain Stem / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D010656:Phenylephrine / Q000378:metabolism; D011311:Pressoreceptors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014667:Vasopressins / Q000378:metabolism*
D065092:Antidiuretic Hormone Receptor Antagonists; D014667:Vasopressins; D001127:Arginine Vasopressin; D010656:Phenylephrine; D000431:Ethanol; C025043:vasopressin, 1-(1-mercaptocyclohexaneacetic acid)-2-(O- methyl-L-tyrosine)-8-L-arginine-