Korean J Physiol Pharmacol.  2000 Apr;4(2):105-111.

Muscarinic receptor subtype controlling the carbachol-induced muscle contraction in guinea pig gastric antrum

• Rhee JC
• Uhm DY
• Kang TM

Abstract

Stimulation of muscarinic receptors by carbachol (CCh) in the circular smooth muscle of the guinea pig gastric antrum causes muscle contraction. In the present study, muscarinic receptor subtype controlling the muscle contraction in response to CCh was studied using putative muscarinic receptor antagonists. Isometric force of the isolated circular muscle strips was measured in an organ bath. CCh contracted the muscle in a dose-dependent way, and each of the three muscarinic receptor antagonists, 4-diphenylacetoxy-N-methylpeperdine methiodide (4-DAMP), methoctramine and pirenzepine shifted the concentration-response curves to the right without significantly reducing the maximum force. The affinities of the muscarinic antagonists (pA2 values) obtained from Schild plot analysis were 10.15, 7.05 and 6.84 for 4-DAMP, methoctramine and pirenzepine, respectively. These results suggest that the M3-subtype mainly mediate the muscle contraction in response to CCh in guinea pig gastric antrum.

Keyword

Muscarinic receptor subtype; Carbachol; Smooth muscle

MeSH Terms

Animals
Baths
Carbachol
Guinea Pigs*
Guinea*
Muscarinic Antagonists
Muscle Contraction*
Muscle, Smooth
Pirenzepine
Pyloric Antrum*
Receptors, Muscarinic*
Carbachol
Muscarinic Antagonists
Pirenzepine
Receptors, Muscarinic