Effect of galanin on smooth muscle contractions in the guinea-pig ileum

The muscarinic receptors of muscularis mucosa have some recognition properties that suggest they resemble receptors of the M1 sybtype. The nerves of these tissues also contain muscarinic receptors which inhibit tonic contractions caused by release of a substance-P-like material by field stimulation. These receptors also appear to be M1 in type as they are maximally activated by McNeil A343 as well as by carbachol (pD2, 5.5 and 7.5, respectively). They are also inhibited by pirenzepine, as well as by atropine (negative logarithms of the required dose for 50% inhibition or potentiation, 6.6–6.7 compared with 8.2–8.3). Hexahydrosiladifenidol, an antagonist selective for M2 receptors of guinea pig ileum, had a low (~7.1) pA2 value for antagonism of both agonists in smooth muscle in this tissue. However, it was closer to atropine in potency with respect to potentiating tonic responses to field stimulation or to inhibiting phasic responses to field stimulation than it was to antagonizing smooth muscle contractions. Thus, atropine was about 40 times more potent than pirenzepine and 2–5 times more potent than hexahydrosilafenidol. There were some quantitative differences in the effectiveness of these three antagonists in blocking the phasic (acetylcholine-mediated) response to field stimulation. Atropine was 70–100 times more potent than pirenzepine and 8–25 times more potent than hexahydrosiladifenidol. This greater potency difference for inhibition of phasic contractions compared with potentiation of tonic contractions was discussed. This tissue appears to be one of the first smooth muscles in which both nerves and muscles contain muscarinic receptors with some recognition properties resembling those of the M1 subtype.

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Role of intracellular Ca2+ stores in smooth muscle contractions of the guinea pig vas deferens

Urological Research ◽

10.1007/bf00296828 ◽

1993 ◽

Vol 21 (5) ◽

pp. 319-323 ◽

Cited By ~ 7

Author(s):

P. Drescher ◽

R. E. Eckert ◽

P. O. Madsen

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Vas Deferens ◽

Muscle Contractions ◽

Smooth Muscle Contractions

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Inhibitory Effect of Sex Steroids on Guinea-Pig Airway Smooth Muscle Contractions

Comparative Biochemistry and Physiology Part C Pharmacology Toxicology and Endocrinology ◽

10.1016/s0742-8413(97)00029-7 ◽

1997 ◽

Vol 118 (1) ◽

pp. 5-10 ◽

Cited By ~ 29

Author(s):

Mercedes Perusquı́a ◽

Ricardo Hernández ◽

Luis M Montaño ◽

Carlos M Villalón ◽

Marı́a G Campos

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Airway Smooth Muscle ◽

Sex Steroids ◽

Inhibitory Effect ◽

Muscle Contractions ◽

Smooth Muscle Contractions

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Effect of CB1 Ligands on Neurogenic and Myogenic Contractile Responses in the Guinea-Pig Ileum

Pharmacology ◽

10.1159/000488682 ◽

2018 ◽

Vol 101 (5-6) ◽

pp. 330-336 ◽

Cited By ~ 1

Author(s):

Josef Donnerer ◽

Ingrid Liebmann

Keyword(s):

Smooth Muscle ◽

Guinea Pig ◽

Cannabinoid Receptor ◽

Allyl Isothiocyanate ◽

Mustard Oil ◽

Inhibitory Effects ◽

Guinea Pig Ileum ◽

Sr 141716A ◽

Smooth Muscle Contractions ◽

Evoked Contractions

This study aimed at investigating whether the synthetic cannabinoid receptor agonist (+)-WIN 55212-2 has neurogenic and myogenic relaxant effects on the longitudinal muscle-myenteric plexus (LMMP) strip of the guinea-pig ileum. (+)-WIN 55212-2, 1–1,000 nmol/L, concentration-dependently inhibited both the electrical stimulation-induced cholinergic twitch responses as well as the myogenic smooth muscle contractions in the LMMP preparation. SR-141716A (rimonabant) 1–1,000 nmol/L, the cannabinoid CB1 receptor antagonist, being without effect on its own, antagonized the (+)-WIN 55212-2-induced effects. The allyl isothiocyanate (mustard oil, 100 µmol/L) induced a relaxant effect in the guinea-pig ileum, which can be regarded as neurogenic and myogenic, was augmented by (+)-WIN 55212-2, and inhibited by SR-141716A. (+)-WIN 55212-2 only moderately modified the 60 mmol/L KCl-evoked contractions. These results provide functional evidence that the CB1 agonist (+)-WIN 55212-2-induced inhibitory effects in the guinea-pig ileum are exerted both at the neuronal as well as at the intestinal smooth muscle cell level.

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