Indomethacin prevents the L-NAME-induced increase in plasma levels of oxytocin in dehydrated rats.
Inhibiting NO synthase (NOS) with N(G)-nitro-L-arginine methyl ester (L-NAME, 250 microg/5 microl of artificial cerebrospinal fluid (aCSF)) injected intracerebroventricularly (i.c.v.) increased already enhanced levels of oxytocin, but not vasopressin, in conscious adult male Sprague-Dawley rats dehydrated for 24 h. Intracerebroventricular pretreatment with indomethacin (200 microg/5 microl aCSF), an inhibitor of cyclo-oxygenase, but not with losartan (25 microg/5 microl aCSF), an antagonist of angiotensin II (ANG II) AT(1)-receptor subtype, nearly prevented the elevation in oxytocin levels after L-NAME. Thus, NO inhibits prostaglandin (but not ANG II) mediated the modulatory actions of NO on oxytocin secretion from the hypothalamo-neurohypophysial system (HNS) during water deprivation.
Kadekaro
M
M
The University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555-0517, USA. mkutyna@utmb.edu
Terrell
M L
ML
Liu
H
H
Bui
V
V
Summy-Long
J Y
JY
D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D003681:Dehydration / Q000097:blood* / Q000473:pathology / Q000503:physiopathology; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology*; D007276:Injections, Intraventricular; D019808:Losartan / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000378:metabolism; D010121:Oxytocin / Q000097:blood* / Q000187:drug effects / Q000378:metabolism*; D011453:Prostaglandins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014667:Vasopressins / Q000097:blood / Q000187:drug effects / Q000378:metabolism; D014868:Water Deprivation / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology
D011453:Prostaglandins; D014667:Vasopressins; D000804:Angiotensin II; D009569:Nitric Oxide; D010121:Oxytocin; D019001:Nitric Oxide Synthase; D019808:Losartan; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin