Characteristics of P2X purinoceptors in the membrane of rat trigeminal ganglion neurons.
The characteristics of purinoceptors in the membrane of rat trigeminal ganglion (TG) neurons were studied by using whole- cell patch clamp technique. The results showed that most of neurons examined (78.9%, 142/180) 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%, 3/142) with an outward current, and the rest (2.8%, 4/142) with biphasic current. Small sized cells (<30 mum) responded to ATP with a rapid desensitizing inward current and were highly sensitive to vanilloid; the medium sized cells (30~40 mum) responded to ATP with slow desensitizing inward current and were not sensitive to vanilloid; while the majority of large sized cells (>40 mum) 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.
Gu
Yuan-Zheng
YZ
Department of Neurobiology, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China.
Yin
Guang-Fu
GF
Guan
Bing-Cai
BC
Li
Zhi-Wang
ZW
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D009474:Neurons / Q000378:metabolism* / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D058469:Receptors, Purinergic P2X / Q000502:physiology*; D012668:Trigeminal Ganglion / Q000166:cytology / Q000378:metabolism* / Q000502:physiology
D058469:Receptors, Purinergic P2X; D000255:Adenosine Triphosphate