Differences in the effects (in vitro) of ethylenediamine on the guinea-pig and rat intestine.
The effects of ethylenediamine in different regions of the rat and guinea-pig small intestine were investigated pharmacologically using isolated gut-bath preparations. In the guinea-pig, ethylenediamine caused concentration-dependent neurally mediated contractions or biphasic responses (contraction followed by relaxation). The contractions could be prevented by muscarinic and GABAA receptor antagonists. Ethylenediamine-evoked relaxations and depression of electrically evoked cholinergic twitch responses were blocked by desensitization to baclofen. However, in the rat intestine, the primary response to applied ethylenediamine was a concentration-dependent, non-desensitizing relaxation, evidently due to a direct action of ethylenediamine on the muscularis since it was unaffected by tetrodotoxin or GABAergic blockade.
Krantis
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Department of Physiology, University of Ottawa, Ontario, Canada.
Khalil
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McKay
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D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation; D005029:Ethylenediamines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000187:drug effects; D007583:Jejunum / Q000187:drug effects; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D005029:Ethylenediamines; D005680:gamma-Aminobutyric Acid; C031234:ethylenediamine; D001418:Baclofen; D001640:Bicuculline