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Characteristics of P2X purinoceptors in the membrane of rat trigeminal ganglion neurons

Gu Yuanzheng, Yin Guangfu, Guan Bingcai, Li Zhiwang

Department of Neurobiology, Tongji Medical College of Huazhong University of Science and Technology.Wuhan 430030,Hubei

Abstract

The characteristics of purinoceptors in the membrane of rat trigeminal ganglion （TG） neurons were studied by using wholecell patch clamp technique. The results showed that most of neurons examined （78.9%, 1421180） were responsive to ATP in a concentration-dependent manner; the others （21.1%, 38/180） were ATP insensitive. Of the ATP-sensitive cells, the majority （95.1%, 135/142） responded to ATP with an inward current, a few （2.1%, 31142） with an outward current, and the rest （2.8%, 4/142） with biphasic current. Small sized cells （<30 #mu#m） responded to ATP with a rapid desensitizing inward current and were highly sensitive to vanilloid; the medium sized ceils （30--40#mu#m） responded to ATP with slow desensitizing inward current and were not sensitive to vanilloid; while the majority of large sized cells （>40#mu#m） did not respond to ATP and vanilloid. The waveform of ATP-activated inward currents was related to the cell diameter. The I-V curves for both small and medium sized cells manifested obvious inward rectification. Furthermore, we studied the kinetic features of ATP-activated currents and the effects of P2 purinoceptor agonists and antagonists on I ATP. The findings suggest that ATP receptor-ion channels are expressed differently among different types of rat TG neurons.

Key words: adenosine triphosphate;purinoceptor;trigeminal ganglion;patch clamp technique

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Citing This Article：

Gu Yuanzheng, Yin Guangfu, Guan Bingcai, Li Zhiwang. Characteristics of P2X purinoceptors in the membrane of rat trigeminal ganglion neurons. Acta Physiol Sin 2006; 58 (2): (in Chinese with English abstract).