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

Pharmacology ◽  
2018 ◽  
Vol 101 (5-6) ◽  
pp. 330-336 ◽  
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.

Muscarinic receptors on nerves and muscles in opossum esophagus muscularis mucosa

1987 ◽  
Vol 65 (9) ◽  
pp. 1903-1907 ◽  
Author(s):  
E. E. Daniel ◽  
J. Jury ◽  
P. Bowker
Keyword(s):  
Smooth Muscle ◽  
Substance P ◽  
Guinea Pig ◽  
Muscarinic Receptors ◽  
Smooth Muscles ◽  
Muscle Contractions ◽  
Muscularis Mucosa ◽  
Field Stimulation ◽  
Guinea Pig Ileum ◽  
Smooth Muscle Contractions

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.

scholarly journals VERAPAMIL AND LOPERAMIDE

2010 ◽  
Vol 17 (02) ◽  
pp. 269-273
Author(s):  
MANZOOR AHMED UNAR ◽  
GULSHAN ARA JALBANI ◽  
MAHBOOB AHMED WAGAN ◽  
Shaheen Shah
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Calcium Channel ◽  
Calcium Concentration ◽  
Free Calcium ◽  
Channel Blockers ◽  
Inhibitory Effects ◽  
Guinea Pig Ileum ◽  
Specific Effects ◽  
Gastrointestinal Motor

Background: In smooth muscle cells, an increase in cytosolic free calcium concentration is an essential step for the cells to contract. The increase in calcium concentration occurs by influx from the extra cellular medium through calcium ion channels. Calcium channels have potential role in regulation of motility in gastrointestinal tract so there is growing interest in calcium channel blockers as a potential pharmacological approach to the treatment of various gastrointestinal motor disorders. In this study we evaluate the inhibitory effects of verapamil on spontaneous contractions of isolated guinea pig ileum and compare them with inhibitory effects of loperamide. Materials and Methods: Isolated intestinal segments of sixteen guinea pigs were used in this study. Serial dilutions (10-18 - 10-3 gm/ml) of loperamide and verapamil were administered; effects observed and recorded by 7B Grass Polygraph machine. Results: We observed that at lower concentrations, loperamide showed more inhibitory effects than verapamil while at higher concentrations (10-4 and 10-3 gm/ml) verapamil showed more inhibitory effects than loperamide on the contractions of isolated guinea pig ileum. Conclusion: This study gave us a clue that verapamil found a potent inhibitor of small intestinal contractions as loperamide. However one can presume further that calcium channel blocker verapamil acting on calcium channel receptor on GIT will be developed with more specific effects on smooth muscle of intestinal tract.

Inhibitory effects of quercetin on guinea-pig ileum contractions

1996 ◽  
Vol 10 (1) ◽  
pp. 66-69 ◽  
Author(s):  
J. Gálvez ◽  
J. Duarte ◽  
F. Sánchez de Medina ◽  
J. Jiménez ◽  
A. Zarzuelo
Keyword(s):  
Guinea Pig ◽  
Inhibitory Effects ◽  
Guinea Pig Ileum
Sign in / Sign up

Export Citation Format

Share Document