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Role of the medial medulla in the inhibitory effect of somatic afferent nerve stimulation on ventricular extrasystoles induced by hypothalamic stimulation in the rabbit

Xia Ying, Guo Xueqin, Li Peng

Department of Physiology, Shanghai First Medical College. Shanghai, China

Abstract

Microinjection of cinanserine (4 #mu#g in 2 #mu#l) into the medial mudulla attenuated the inhibitory effect of somatic afferent nerve stimulation on the hypothalamic stimulation-induced ventricular extrasystoles (HVEs), while microinjection of naloxone (4 #mu#g in 2 #mu#l) into the same area completely blocked the inhibitory effect. The number of HVEs was reduced following microinjection of either 5-HT or morphine into the central gray matter. This effect of 5-HT or morphine microinjection was abolished after destroying the medial portion of the medulla. These results suggest that the inhibitory effect of somatic afferent nerve stimulation on HVEs is mediated by activation of opiate and serotonin receptors in the medial medulla. The neural mechanism of the inhibitory effect of somatic afferent stimulation on HVEs is discussed.

Key words: Central gray matter;Cinanserine;Hypothalamus;Midline region of the medulla;Naloxone;Somatic afferent nerve stimulation;Ventricular extrasystole

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Citing This Article：

Xia Ying, Guo Xueqin, Li Peng. Role of the medial medulla in the inhibitory effect of somatic afferent nerve stimulation on ventricular extrasystoles induced by hypothalamic stimulation in the rabbit. Acta Physiol Sin 1985; 37 (1): (in Chinese with English abstract).