Central alpha-adrenoceptor influence over the cardiovascular reflexes activated by veratrine.
Intravenous veratrine induced alterations in cardiovascular parameters in cats were used as a tool for assessing the influence of central alpha-adrenoceptors over reflex adjustments in the heart rate and blood pressure. Blockade of central alpha 2-adrenoceptors with idazoxan or yohimbine, inhibited, while their activation by clonidine, as also blockade of alpha 1-adrenoceptors, with prazosin, potentiated the veratrine induced bradycardia. The hypotensive effect was relatively unaltered by these treatments. Low doses of clonidine potentiated the veratrine-induced bradycardia. It appears that alpha 2-adrenoceptor mechanisms exert greater control over the reflex regulation of heart rate than over reflex control of blood pressure.
Gurtu
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Pant
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Sinha
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D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002415:Cats; D006339:Heart Rate / Q000187:drug effects*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D014702:Veratrine / Q000494:pharmacology*
D011942:Receptors, Adrenergic, alpha; D014702:Veratrine