Neural and endocrine circuits mediating inhibition of bradykinin-induced plasma extravasation by subcutaneous and spinal-intrathecal nicotine.
In this study we evaluated the mechanisms underlying s.c. and spinal intrathecal (i.t.) nicotine inhibition of bradykinin-induced plasma extravasation in the knee joint of the rat (J. Pharmacol. Exp. Ther. 262: 889-895, 1992; ibid., 264: 839-844, 1993). The dose-response curve for the inhibitory action of s.c. nicotine on bradykinin-induced plasma extravasation was attenuated by adrenal medullectomy and by intra-articular perfusion of ICI-118,551 (a beta-2 adrenoceptor antagonist). In addition, the dose-response curve of s.c. nicotine was attenuated by acute surgical lumbar sympathectomy and by intra-articular phentolamine (an alpha adrenoceptor antagonist). The dose-response curve for i.t. nicotine (up to 1 mg/kg) was not attenuated by intra-articular ICI-118,551 and was potentiated by adrenal medullectomy. The action of i.t. nicotine was also not affected by intra-articular phentolamine or by acute surgical lumbar sympathectomy. These results suggest that the inhibition of bradykinin-induced plasma extravasation in the knee joint of the rat by s.c., but not i.t., nicotine is mediated through the sympathoadrenal and sympathetic systems.
Miao
F J
FJ
Department of Medicine, School of Medicine, University of California at San Francisco, USA.
Benowitz
N
N
Levine
J D
JD
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000097:blood*; D007278:Injections, Spinal; D007279:Injections, Subcutaneous; D007719:Knee Joint / Q000187:drug effects*; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D010646:Phentolamine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D009538:Nicotine; D001920:Bradykinin; D010646:Phentolamine