TY - JOUR
T1 - Characterization of muscarinic receptors in canine bronchial smooth muscle
AU - O'Rourke, Stephen T.
AU - Flavahan, Nicholas A.
AU - Vanhoutte, Paul M.
N1 - Funding Information:
Acetylcholine, added exogenously or released from cholinergic nerves, causes contraction of canine bronchial smooth muscle. The contractile response to acetylcholine is mediated by muscarinic receptors since it is antagonized by low concentrations of atropine (Vermeire and Van-houtte, 1979). Muscarinic receptors can now be divided into two distinct subtypes (i.e. M 1 and M2) based on both functional and biochemical studies (Hammer and Giachetti, 1982). The aim of the present investigation was to characterize the receptors activated by acetylcholine in canine bronchial smooth muscle by using selective M1-and M2-muscarinic antagonists. Moreover, since exogenous and nerve-released neurotransmitters This work was supported by National Institutes of Health Grant HL 21584 and National Research Service Award HL 07340 (S.T. O'Rourke). * To whom all correspondence should be addressed: Depart-ment of Physiologya nd Biophysics, Mayo Clinic, Rochester, MN 55905, U.S.A.
PY - 1987/8/4
Y1 - 1987/8/4
N2 - Rings of canine bronchi were suspended for isometric tension recording. Contractions produced by exogenously added acetylcholine were inhibited by pirenzepine and pancuronium. The pKB values were 6.76 for pirenzepine (calculated at 10-6 M) and 5.30 and 5.13 for pancuronium (calculated at 10-5 and 3 × 10-5 M, respectively). Contractile responses evoked by cholinergic nerve stimulation (0.2-16 Hz, 9 V) were depressed by pancuronium in a concentration-dependent manner, while concentrations of pirenzepine selective for M1-muscarinic receptors were without effect. The results indicate that exogenous and nerve-released acetylcholine activate a homogenous population of M2-muscarinic receptors in isolated preparations of canine bronchial smooth muscle.
AB - Rings of canine bronchi were suspended for isometric tension recording. Contractions produced by exogenously added acetylcholine were inhibited by pirenzepine and pancuronium. The pKB values were 6.76 for pirenzepine (calculated at 10-6 M) and 5.30 and 5.13 for pancuronium (calculated at 10-5 and 3 × 10-5 M, respectively). Contractile responses evoked by cholinergic nerve stimulation (0.2-16 Hz, 9 V) were depressed by pancuronium in a concentration-dependent manner, while concentrations of pirenzepine selective for M1-muscarinic receptors were without effect. The results indicate that exogenous and nerve-released acetylcholine activate a homogenous population of M2-muscarinic receptors in isolated preparations of canine bronchial smooth muscle.
KW - (Canine)
KW - Acetylcholine
KW - Bronchi
KW - Electrical stimulation
KW - Muscarinic receptors
KW - Pancuronium
KW - Pirenzepine
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U2 - 10.1016/0014-2999(87)90643-1
DO - 10.1016/0014-2999(87)90643-1
M3 - Article
C2 - 3622620
AN - SCOPUS:0023183233
SN - 0014-2999
VL - 140
SP - 117
EP - 120
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
IS - 1
ER -