Antagonism of acetylcholine action in guinea-pig tracheal smooth muscle and epithelium by pirenzepine, 4-DAMP and atropine.
Acetylcholine-induced guinea-pig tracheal smooth muscle contraction and epithelium-derived relaxant factor release were evaluated using guinea-pig open tracheal rings and rat anococcygeus muscle bioassay to get insight into the participation of muscarinic receptor subtypes in these responses. There was a significant difference between the two pA2 values obtained in contraction and relaxation experiments for pirenzepine, but no difference was found either for atropine or for 4-DAMP. This difference seems to be due to the participation of M1-receptors in smooth muscle contraction.
Orer
H S
HS
Department of Pharmacology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Guc
M O
MO
Rezaki
Y E
YE
Ilhan
M
M
Kayaalp
S O
SO
D000109:Acetylcholine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D004848:Epithelium / Q000187:drug effects; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D010880:Piperidines / Q000494:pharmacology*; D010890:Pirenzepine / Q000494:pharmacology*; D051381:Rats; D014132:Trachea / Q000187:drug effects
D010880:Piperidines; D010890:Pirenzepine; D001285:Atropine; C042375:4-diphenylacetoxy-1,1-dimethylpiperidinium; D000109:Acetylcholine