Osmolality-induced tuning of action potentials in trigeminal ganglion neurons.
The present study explored the effect of anisotonicity on action potential (AP) in cultured trigeminal ganglion (TG) neurons. We demonstrate that the number of evoked APs was increased by both hypo- and hypertonic treatment. Transient Receptor Potential Vanilloid 4 receptor (TRPV4) activator increased the number of APs, but only hypotonic-response was markedly blocked in TRPV4-/- mice. Additionally, inhibition of PKC attenuated hypotonicity-induced increase, whereas antagonism of PKA attenuated hypertonicity-response. We conclude that anisotonicity increases excitability of nociceptors, which might be involved in anisotonicity-induced nociception. The increase of APs by hypo- and hypertonicity is mediated through different receptor and intracellular signaling pathways.
Chen
Lei
L
Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China. chenltj@hotmail.com
Liu
Changjin
C
Liu
Lieju
L
D000200:Action Potentials / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D002478:Cells, Cultured; D006982:Hypertonic Solutions / Q000494:pharmacology; D007038:Hypotonic Solutions / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009994:Osmolar Concentration; D018408:Patch-Clamp Techniques / Q000379:methods; D010703:Phorbol Esters / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D050916:TRPV Cation Channels / Q000172:deficiency; D012668:Trigeminal Ganglion / Q000166:cytology*
D006982:Hypertonic Solutions; D007038:Hypotonic Solutions; D010703:Phorbol Esters; D050916:TRPV Cation Channels; C486576:Trpv4 protein, mouse; C008876:phorbol-12,13-didecanoate; D002211:Capsaicin