| 2884938 |
Hsu WH, Shaw RN, Schaffer DD, Crump MH, Greer MH: Further evidence to support the alpha 2-adrenergic nature of amitraz-induced decrease in intestinal motility. Arch Int Pharmacodyn Ther. 1987 Mar;286(1):145-51.
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. |
6(0,0,1,1) |