Inositol trisphosphate-induced hyperpolarization in rat dorsal root ganglion neurons.
Inositol 1,4,5-trisphosphate (1,4,5-InsP3) was perfused into rat dorsal root ganglion (DRG) neurons by whole-cell patch-clamp electrodes, while measuring the membrane potential. This operation evoked a transient (2-3 min) membrane hyperpolarization of about -15 mV (from -42 mV) followed by a depolarization. The membrane hyperpolarization was abolished when 30 mM EGTA was perfused together with 1,4,5-InsP3 or when 0.2 mM quinine was added to the bath solution. The hyperpolarizing response was enhanced when a low-Ca2+ EGTA-free intracellular solution was used. Two InsP2 isomers induced a different response. Our results suggest that the hyperpolarization is due to 1,4,5-InsP3-induced Ca2+ release which may trigger Ca-sensitive K+ channels to open. Present results show that cultured DRG neurons are able to respond to 1,4,5-InsP3 perfusion in the whole-cell configuration.
Wang
Z
Z
Department of Physiology, University of Leiden, The Netherlands.
Ypey
D L
DL
Van Duijn
B
B
D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects*; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010477:Perfusion; D051381:Rats
D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium