Premium
Nitric oxide inhibits the dopamine‐induced K + current via guanylate cyclase in aplysia neurons
Author(s) -
Sawada Masashi,
Ichinose Mitsuyuki,
Stefano George B.
Publication year - 1997
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(19971101)50:3<450::aid-jnr11>3.0.co;2-a
Subject(s) - sodium nitroprusside , ibmx , nitric oxide , phosphodiesterase inhibitor , chemistry , nitric oxide synthase , patch clamp , biophysics , intracellular , pharmacology , cyclic guanosine monophosphate , biochemistry , forskolin , biology , receptor , organic chemistry
Nitric oxide (NO) is produced by the enzyme nitric oxide synthase (NOS) and has been implicated in inter‐ and intracellular communication in the nervous system. The present study was undertaken to assess the effects of sodium nitroprusside (SNP) and hydroxylamine (HOA), NO donors, on a dopamine (DA)‐induced K + current in identified Aplysia neurons using voltage‐clamp and pressure ejection techniques. Bath‐applied SNP (10–25 μM) reduced the DA‐induced K + current without affecting the resting membrane conductance and holding current. The DA‐induced K + current also was inhibited by the focal application of 200 μM HOA to the neuron somata. The DA‐induced K + current suppressing effects of SNP and HOA are completely reversible. Pretreatment with 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ; 1 μM), a specific inhibitor of NO‐stimulated guanylate cyclase, and hemoglobin (50 μM), a nitric oxide scavenger, decreased the SNP‐induced inhibition of the DA‐induced current. In contrast, intracellular injection of 1 mM guanosine 3′,5′‐cyclic monophosphate (cGMP) or bath‐applied 3‐isobutyl‐1‐methylxanthine (IBMX; 50 μM), a nonspecific phosphodiesterase inhibitor, inhibited the DA‐induced current, mimicking the effect of the NO donors. These results demonstrate that SNP and HOA inhibit the DA‐induced K + current and that the mechanism of NO inhibition of the DA‐induced current involves cGMP‐dependent protein kinase. J. Neurosci. Res. 50:450–456, 1997. © 1997 Wiley‐Liss, Inc.