Possible role of central alpha 1-adrenoceptors in the control of the autonomic nervous system in normotensive and spontaneously hypertensive rats.
The cardiovascular effects of AR-C 239, a new and selective alpha 1-adrenoceptor blocking drug were studied in normotensive and spontaneously hypertensive rats (SHR). AR-C 239 (300 micrograms/kg i.v.) did not change the heart rate in control (without pretreatment) and bilaterally vagotomized normotensive rats, but induced significant bradycardia in rats pretreated with a beta-adrenoceptor blocking drug. This bradycardic effect was inhibited by atropine or bilateral vagotomy. In SHR, the administration of AR-C 239 reduced heart rate in the control, bilaterally vagotomized and beta-blocked rats. Blood pressure was decreased in the same way in the two rat strains. It is suggested that central alpha 1-adrenoceptors could participate in the control of vagal tone in normotensive and SH rats, and of sympathetic activity in the SHR only.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure; D006339:Heart Rate; D006973:Hypertension / Q000503:physiopathology*; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D010879:Piperazines; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D007546:Isoquinolines; D010879:Piperazines; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; C032994:AR-C239