Investigations into the mechanism of morphine and ethanol inhibition in the guinea pig ileum longitudinal muscle strip

1980 ◽  
Vol 58 (3) ◽  
pp. 265-270 ◽  
Author(s):  
John G. Clement
Keyword(s):  
Guinea Pig ◽  
Muscarinic Receptors ◽  
Longitudinal Muscle ◽  
Opiate Receptor ◽  
Muscle Strip ◽  
Ethanol Inhibition ◽  
Twitch Response ◽  
Mechanism Of Inhibition ◽  
Ethanol Ethanol ◽  
A Site

It has been noted that the analgesic property of ethanol bears a marked resemblance to that of morphine. The purpose of this study was to determine if the mechanism of action of morphine and ethanol was similar using the guinea pig ileal longitudinal muscle strip (GPI-LMS). Ethanol (35–260 mM) depressed the twitch response and the acetylcholine- (ACh-), KCl-, and BaCl2-induced contractions to the same extent while having no significant effect on the binding of [3H]quinuclidinyl benzilate ([3H]QNB) to muscarinic receptors. Morphine (53–530 nM) inhibited the twitch response and to a lesser extent BaCl2- and KCl-induced contractions while having no significant effect on either ACh-induced contractions or the binding of [3H]QNB to muscarinic receptors. Naloxone and increased [Ca2+] reversed the inhibitory effects of morphine but not ethanol. Ethanol appears to inhibit a site after interaction of ACh with the receptor. Mechanism of inhibition of BaCl2 response is also different as naloxone and increased [Ca2+] reverse morphine but not ethanol inhibition. Ethanol inhibition in GPI-LMS does not involve the opiate receptor.

The effect of amitriptyline, mianserin, and viloxazine at pre- and post-junctional muscarinic receptors in guinea-pig ileal longitudinal muscle

1982 ◽  
Vol 60 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Y. H. Kwok ◽  
F. Mitchelson
Keyword(s):  
Electrical Stimulation ◽  
Guinea Pig ◽  
Muscarinic Receptors ◽  
Longitudinal Muscle ◽  
Fold Increase ◽  
Selective Inhibition

The antimuscarinic activity of amitriptyline, mianserin, and viloxazine was compared with atropine in guinea-pig ileal longitudinal muscle. The pA2 values obtained using carbachol (CCh) as agonist were as follows: atropine, 9.55; amitriptyline, 7.50; mianserin, 6.40; and viloxazine, 4.91. Responses to transmural electrical stimulation (1–50 Hz) were more resistant than those produced by CCh to inhibition by atropine and the antidepressants. This did not appear to be due to a selective inhibition of prejunctional inhibitory muscarinic receptors, as a pA2 of 8.73 was obtained with atropine for the depression of oxotremorine-induced inhibition of acetylcholine (ACh) output. Amitriptyline (10 μM) caused a 2.4-fold increase in ACh output and was 200-fold weaker than atropine at doubling ACh output in the longitudinal muscle stimulated at 0.3 Hz. Mianserin (10 μM) and viloxazine (1–10 μM) did not significantly affect ACh output. It is suggested that the antidepressants exhibit a greater affinity for the postjunctional muscarinic receptors in the guinea-pig ileal longitudinal muscle.

Effect of ascorbate on the contractile response induced by DMPP in guinea-pig ileal longitudinal muscle strip

1983 ◽  
Vol 89 (3-4) ◽  
pp. 229-234 ◽  
Author(s):  
Eiichi Hayashi ◽  
Kazumasa Shinozuka ◽  
Toshio Maeda ◽  
Mitsuhiro Takeda
Keyword(s):  
Guinea Pig ◽  
Longitudinal Muscle ◽  
Contractile Response ◽  
Muscle Strip

The analysis of post-tetanic potentiation in guinea-pig ileum longitudinal muscle strip

1982 ◽  
Vol 79 (3-4) ◽  
pp. 245-255 ◽  
Author(s):  
Ondřej Kadlec ◽  
Isidor Šeferna ◽  
Karel Mašek ◽  
George T. Somogyi ◽  
Joseph Knoll
Keyword(s):  
Guinea Pig ◽  
Longitudinal Muscle ◽  
Muscle Strip ◽  
Guinea Pig Ileum ◽  
Post Tetanic Potentiation
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