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Inhibition of the glutamate‐induced K + current in identified onchidium neurons by nitric oxide donors
Author(s) -
Sawada Masashi,
Ichinose Mitsuyuki,
Anraku Mitsuo
Publication year - 2000
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(20000601)60:5<642::aid-jnr9>3.0.co;2-#
Subject(s) - sodium nitroprusside , nitric oxide , ibmx , chemistry , phosphodiesterase inhibitor , glutamate receptor , biophysics , cyclic guanosine monophosphate , guanosine , pharmacology , biochemistry , medicine , endocrinology , biology , forskolin , receptor , organic chemistry
Nitric oxide (NO) acts as a neurotransmitter and neuromodulator in the nervous system of many vertebrates and invertebrates. The effects of extracellularly applied sodium nitroprusside (SNP) and diethylamine NO (C 2 H 5 ) 2 N[N(O)NO]‐Na + (DEA/NO), NO donors, on a glutamate (Glu)‐induced K + current in identified Onchidium neurons were investigated using voltage clamp and pressure ejection techniques. Bath‐applied SNP (10 μM) and DEA/NO (5–10 μM) reduced the Glu‐induced K + current without affecting the resting membrane conductance and holding current. The Glu‐induced K + current also was inhibited by the focal application of SNP to the neuron somata. The suppressing effects of NO donors were concentration‐dependent and completely reversible. Pretreatment with hemoglobin (50 μM), a nitric oxide scavenger, and 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ; 1 μM), a specific inhibitor of NO‐stimulated guanylate cyclase, decreased the SNP‐induced inhibition of the Glu‐induced current. Bath‐applied 50 μM 3‐isobutyl‐1‐methylxanthine (IBMX), a nonspecific phosphodiesterase inhibitor, or intracellular injection of 1 mM guanosine 3′,5′‐cyclic monophosphate (cGMP) inhibited the Glu‐induced current, mimicking the effect of NO donors. These results demonstrate that SNP and DEA/NO inhibit the Glu‐induced K + current and that the mechanism of NO inhibition of the Glu‐induced current involves cGMP‐dependent protein kinase. J. Neurosci. Res. 60:642–648, 2000 © 2000 Wiley‐Liss, Inc.