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Neuropeptide Y reduces desensitization of #alpha#_(1)adrenoceptors in rat blood vessels

Dong Erdan, Chen Mingzhe, Han Qide

The Third Hospital, Beijing Medical University. Beijing

Abstract

Vasoconstrictive responses to norepinephrine(NE) in isolated rat aorta and renal artery were respectively taken to represent the biological responses mediated by #alpha#_(1B) and #alpha#_(1A) subtype adrenoceptor(AR). After blood vessels were incubated with 10 #mu#mol/L NE for 2h, #alpha#_(1)-AR mediated vasocontraction was desensitized significantly, #alpha#_(1B)-AR being more marked than #alpha#_(1A)-AR. In the presence of 0.5 #mu#mol/L neuropeptide Y (NPY), desensitization of #alpha#_(1B)-AR was attenuated significantly. In rat aorta the NE-mediated contraction comprised both phasic and tonic elements. After the incubation with NE, the phasic contraction period was prolonged but magnitude decreased, while no change was found for the tonic contraction. In the presence of NPY, the changes of phasic contraction caused by NE preincubation disappeared. It is suggested that retardation and reduction of intracellular Ca~(2+) release were involved in the mechanism for desensitization of #alpha#_(1B)-AR.

Key words: #alpha#_(1)-adrenoceptor;Desensitization;Neuropeptide Y;Receptor subtypes; Blood vessel

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Citing This Article：

Dong Erdan, Chen Mingzhe, Han Qide. Neuropeptide Y reduces desensitization of #alpha#_(1)adrenoceptors in rat blood vessels. Acta Physiol Sin 1994; 46 (4): (in Chinese with English abstract).