Hypotensive responses following oral adminstration of beta-adrenoceptor blocking drugs to the conscious cat.
On oral administration, the non-selective beta-adrenoceptor blocking drugs (+/-)-bufuralol, (-)-bufuralol, propanolol, oxprenolol, pindolol and alprenolol produced hypotensive responses in the conscious cat; (+)-bufuralol was without effect. The selective beta-adrenoceptor blocking drugs practolol and atenolol had no effect on blood pressure but tolamolol elicited a hypotensive response. All the drugs tested reduced the tachycardia due to intravenous isoprenaline in the conscious cat; however, not all doses of these drugs reduced blood pressure. (+)-Bufuralol was devoid to beta-adrenoceptive blocking activity. Only tolamolol reduced the pressor response to i.v. phenylephrine in the conscious cat, indicating that alpha-adrenoceptive blocking activity may contribute to its hypotensive action. The results suggest that beta-adrenoceptive blocking activity is necessary for the hypotensive responses of these drugs. However, for the different drugs, there was no correlation between peripheral beta-adrenoceptive blocking activity and hypotensive response.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002415:Cats; D003864:Depression, Chemical; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D013997:Time Factors
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists