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PubMed · 2884938

Further evidence to support the alpha 2-adrenergic nature of amitraz-induced decrease in intestinal motility.

W H Hsu·R N Shaw·D D Schaffer·M H Crump·M H Greer
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Abstract

The effect of amitraz, a formamidine insecticide, on in vitro intestinal contractions was studied in teh transmurally-stimulated guinea-pig ileum. An electrical stimulation (with 80 V/0.5 msec/0.1 Hz shown on the dial of the stimulator) caused the ileum to contract presumably via the release of acetylcholine. Amitraz (10(-7) to 10(-6) M) produced a dose-dependent inhibition of these transmurally-stimulated contractions. This effect of amitraz was blocked and reversed by idazoxan (10(-6) M), an alpha 2-adrenoceptor antagonist, but was not prevented by prazosin (10(-6) M), an alpha 1-adrenoceptor antagonist. These results suggest that alpha 2-adrenoceptors mediate the effects of amitraz on the transmurally-stimulated guinea-pig ileum. The results also suggest that amitraz decreases intestinal contraction by activating the alpha 2-adrenoceptors in the myenteric (Auerbach's) plexus, thus inhibiting parasympathetic tone.

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Adrenergic alpha-AgonistsAnimalsDepression, ChemicalDioxanesDose-Response Relationship, DrugGastrointestinal MotilityGuinea PigsIdazoxanIleumInsecticidesPrazosinToluidinesJournal Article

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W H Hsu, R N Shaw, D D Schaffer, M H Crump, M H Greer. 1987. Further evidence to support the alpha 2-adrenergic nature of amitraz-induced decrease in intestinal motility.. https://pubmed.ncbi.nlm.nih.gov/2884938/

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