Inhibitory effect of nitric oxide on voltage-dependent calcium currents in rat dorsal root ganglion cells.
The effect of nitric oxide (NO) on calcium current (I(Ca)) and intracellular calcium concentration ([Ca(2+)](i)) in primarily cultured dorsal root ganglion (DRG) neurons was investigated from neonatal rats. I(Ca) and [Ca(2+)](i) were simultaneously recorded using perforated-patch technique in combination with fluorescence measurement from single DRG neurons. NO donors, sodium nitroprusside (SNP) and S-nitro-N-acetylpenicillamine (SNAP), inhibited I(Ca) in small-diameter neurons without significant change in voltage-dependence of activation and activation time constants. SNP and SNAP also reduced the transient [Ca(2+)](i) peak accompanied by I(Ca). Inhibition by NO was reproducible, but gradually desensitized. In some DRG neurons, SNP and SNAP increased basal [Ca(2+)](i) in concentration of 10 microM with little effect on NO-induced inhibition of I(Ca). 8-Br-cGMP, a permeable cGMP analog, mimicked the effects of SNP and SNAP. These results suggest that, in DRG neurons, NO has inhibitory effect on I(Ca), which is independent of NO-induced increase of basal [Ca(2+)](i), through cGMP-dependent pathway.
Kim
S J
SJ
Department of Physiology and Biophysics, Seoul National University College of Medicine, Seoul, 110-799, Korea.
Song
S K
SK
Kim
J
J
D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D017869:Cyclic GMP-Dependent Protein Kinases; D004594:Electrophysiology; D005727:Ganglia, Spinal / Q000166:cytology* / Q000201:enzymology*; D007700:Kinetics; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D020030:Nitric Oxide Donors; C110881:S-nitro-N-acetylpenicillamine; D009599:Nitroprusside; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D011494:Protein Kinases; D017869:Cyclic GMP-Dependent Protein Kinases; D010396:Penicillamine; D006152:Cyclic GMP; D002118:Calcium