Effects of beta adrenergic blocking drugs and trifluperidol on intestinal motility and splanchnic nerve activity in cats.
In cats anaesthetized with chloralose and urethane we studied the effect of the selective beta 1 adrenergic blocking practolol and the non-selective beta 1-2 adrenergic blocking pindolol on the intestinal motility, the efferent sympathetic activity, arterial blood pressure and heart-rate. We compared the effects of trifluperidol on the intestinal tone, the intestinal motility and its duration with those of trifluperidol and practolol combined. It was found that 1-, 2-, and 3 mg/kg of practolol given intravenously had no influence on the spontaneous electric activity of postganglionic fibres of the splanchnic or hypogastric nerves, thus it had no central effect. Accordingly, its site of effect proved to be peripheric. Its administration was associated with a slight decrease of the arterial blood pressure and heart rate. The intestinal tone was instantly increased depending on the does in every case. In two-thirds of our experiments the intestinal motility was restored 1 to 3 minutes following administration depending on the dose. Combined with trifluperidol, practolol produces a further increase in the enhancing activity of trifluperidol on the intestinal tone and motility. It considerably extends the duration of the action of trifluperidol on the intestinal motility. Pindolol increases the intestinal tone and motility dose-dependently in every case, reduces the efferent sympathetic activity, which is inversely proportional to the dose. The action is most pronounced on administration of 0.125 micrograms/kg of pindolol intravenously but it cannot be observed with a dose of 0.5 mg/kg. No significant changes were observed in blood pressure but there was a reduction in heart rate. The action of pindolol is supposed to be both central and peripheral in nature.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D004305:Dose-Response Relationship, Drug; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D010869:Pindolol / Q000008:administration & dosage / Q000494:pharmacology*; D011217:Practolol / Q000008:administration & dosage / Q000494:pharmacology*; D013153:Splanchnic Nerves / Q000187:drug effects*; D013997:Time Factors; D014272:Trifluperidol / Q000008:administration & dosage / Q000494:pharmacology*
D010869:Pindolol; D014272:Trifluperidol; D011217:Practolol