Peroxynitrite produces relaxations on the rat anococcygeus muscle.
Effects of peroxynitrite (ONOO-), its stable product 3-nitrotyrosine (NT) and sodium nitroprusside (SNP) on isolated rat anococcygeus muscle were investigated. Administration of 0.1-1.0 mM ONOO- or 0.01-100.0 microM SNP produced concentration-dependent relaxations on the phenylephrine (2 microM)-precontracted muscle. Time courses of these relaxations to ONOO- and SNP were not similar and decomposed ONOO- caused a biphasic response composed of an initial contraction followed by a relaxation. NT (0.01-0.1 mM) either incubated for 20 min prior to precontraction or given during precontraction plateau did not attenuate precontraction or ONOO(-)-induced relaxations. Results of the present study demonstrate that ONOO- relaxes rat anococcygeus muscle specifically while its stable metabolite NT has no effect.
Hoşgör-Başgut
B
B
Department of Pharmacology, Faculty of Pharmacy, University of Gazi, Ankara, Turkey. bilgenh@yahoo.com
Başgut
E
E
Soyak
G
G
Tunçtan
B
B
Cakici
I
I
Kanzik
I
I
D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009566:Nitrates / Q000494:pharmacology*; D051381:Rats
D009566:Nitrates; C039642:peroxynitric acid