The effect of ethanol on spontaneous contractions and on the contraction produced by periarterial nerve stimulation and by acetylcholine in the rat isolated ileum.
1. The effect of ethanol (0.01-1000 mg.ml-1) on tone, contractility, and the contractions produced by periarterial nerve stimulation and by acetylcholine was studied in the rat isolated ileum. 2. In low concentrations, ethanol reduced the spontaneous contractions by 60 +/- 1.5% and in high concentrations, it produced a marked contraction in the muscle (3.2 +/- 0.3 g, mean +/- SE, n = 6). 3. In the presence of adrenergic, histaminergic, serotonin and prostaglandin antagonists, ethanol (1.8 mg.ml-1) reduced the contractions produced by periarterial nerve stimulation, at 1-100 Hz with 20 V and 0.2 msec pulse duration, by 80 +/- 3.4%. Ethanol also reduced the contractions produced by acetylcholine (0.001-1 microgram.ml-1), the mean EC50 values were 0.1 +/- 0.01 microgram.ml-1, control, and 0.96 +/- 0.1 microgram.ml-1, in ethanol, respectively. 4. Although the mechanism of action of ethanol at the gut smooth muscle is not clear, it is known that it may block conduction, depolarize the cell membrane and cause release of intracellular calcium, which is, in part, responsible for the contraction produced by ethanol in the rat ileum.
Wali
F A
FA
Anaesthetics Unit, London Hospital Medical College, Whitechapel, U.K.
Suer
A H
AH
Hayter
A
A
Tugwell
A C
AC
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D004558:Electric Stimulation; D000431:Ethanol / Q000494:pharmacology*; D007082:Ileum / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009200:Myocardial Contraction / Q000187:drug effects*; D010525:Peripheral Nerves / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains
D000431:Ethanol; D000109:Acetylcholine