Different effects of capsaicin on I(A) and I(K) in pain-conduct neurons of rats.
The different effects of capsaicin on I(A) and I(K) currents in pain-conduct neurons of trigeminal ganglia (TG) were investigated. In cultured TG neurons of rats, whole-cell patch clamp techniques were used to record the I(A) and I(K) before and after capsaicin perfused. Results revealed that 1 micromol/L capsaicin could inhibit the amplitude of I(A) by 48.2% (n = 10, P < 0.05), but had no inhibitory effect on I(K) (n = 7, P > 0.05). Ten micromol/L capsaicin could significantly inhibit the amplitude of I(A) by 93.2% (n = 8, P < 0.01), but only slightly inhibit the amplitude of I(K) by 13.2% (n = 7, P < 0.05). Neither 1 micromol/L nor 10 micromol/L capsaicin had effects on the active curve of I(A) and I(K). It was concluded that capsaicin could selectively inhibit the I(A) current, and this effect might involve in the analgesic mechanisms of capsaicin.
Fu
Hui
H
Department of Pharmacology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Liu
Hui
H
Cao
Xuehong
X
Hu
Yan
Y
Xiang
Jizhou
J
Liu
Lieju
L
D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D002478:Cells, Cultured; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D018408:Patch-Clamp Techniques; D024642:Potassium Channels, Voltage-Gated / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012668:Trigeminal Ganglion / Q000166:cytology
D024642:Potassium Channels, Voltage-Gated; D002211:Capsaicin