Effect of CH-38083, a selective antagonist of alpha 2-adrenoceptors, on renal sympathetic function.
The effects of 7,8-(methylenedioxi)-14-alpha-hydroxyalloberbane HCl (CH-38083), a structurally new, selective and potent alpha 2-adrenoceptor antagonist, and of idazoxan, were studied on both the spontaneous activity of the postganglionic sympathetic renal nerve and on the clonidine- or xylazine-induced inhibitory action in anaesthetized cats. The drug CH-38083 (30-200 micrograms/kg, i.v.) caused a sustained increase of the sympathetic activity and blood pressure. Larger doses of idazoxan (200-500 micrograms/kg, i.v.) were needed to induce similar effects. Both antagonists were effective in antagonizing the sympatho-inhibitory effect of clonidine or xylazine. The excitatory response to selective alpha 2-adrenoceptor antagonists suggests that the sympathetic output undergoes tonic inhibition due to a permanent alpha 2-adrenoceptor stimulation.
Dóda
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Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest.
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D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001599:Berberine / Q000031:analogs & derivatives / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D002415:Cats; D003000:Clonidine / Q000494:pharmacology; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D004146:Dioxanes / Q000494:pharmacology; D005260:Female; D019329:Idazoxan; D007668:Kidney / Q000294:innervation*; D008297:Male; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D014991:Xylazine / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D001600:Berberine Alkaloids; D004146:Dioxanes; D011942:Receptors, Adrenergic, alpha; D001599:Berberine; C048886:7,8-(methylenedioxy)-14-hydroxyberbane; D014991:Xylazine; D004246:Dimethylphenylpiperazinium Iodide; D003000:Clonidine; D019329:Idazoxan