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Effects of low pH and nicotine on carotid body chemoreceptor activity in the rabbit

Zhuang Jiaju, Pang Lei, Dong Li

Department of Pathophysiology, Hebei Academy of Medical Science. Shijiazhuang 050021, Hebei, China

Abstract

The unit discharges of carotid chemosensory afferent fihers were rec0rded in the in vitro carotid body (CB) -sinus nerve preparations (n=55) from 29 ralibits. The results were as follows: (1) The discharge of all the units increased from 0.86+-0.21 to 1.75+-0.40 imp/s (P<0.001) upon lowering the pH of modified Locke solution. (2)Addition of nicotine at doses of 1, 3, 6, 10 and 15 #mu#g/ml to the solution led to a dosedependent increase in the discharge from 0.60+-0.21 to 0.96+-0.21, 1.19+-0.30,1.24+-0.29, 1.48+-0.41 and 1.82+-0.39 imp/s, respectively (r=0.94, P<0.001) n=10). Nicotinic stimulati0n was antagonized by D-tub0curarine but the basal discharge was not significantly affected. (3) Superfusion of the CB with acid solution increased the discharge from 0.95+-0.34 to 1.84+-0.55 imp/s (P<0.01, n=19);Afer injections of nicotine 1～5 #mu#g/ml to acid perfusate the unit discharge showed an increase from 0.96+-0.25 to 1.53+-0.24 imp/s.

Key words: Acetylecholine;Carotid body chemoreceptor;Afferent unit discharee;N-receptor;Low pH

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Citing This Article：

Zhuang Jiaju, Pang Lei, Dong Li. Effects of low pH and nicotine on carotid body chemoreceptor activity in the rabbit. Acta Physiol Sin 1997; 49 (5): (in Chinese with English abstract).