Inhibition of depolarization-induced nitric oxide synthase activation by NS-7, a phenylpyrimidine derivative, in primary neuronal culture.
Neuronal nitric oxide synthase (NOS) is considered to be involved in the pathogenesis of ischemic brain damage. In the present study, the effect of a novel neuroprotective phenylpyrimidine derivative, 4-(4-fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy)pyrimidine hydrochloride (NS-7), on depolarization-stimulated NOS activity was examined in cultured neurons of mouse cerebral cortex. Various depolarizing stimuli such as veratridine, KCl, and N-methyl-D-aspartate increased the NOS activity determined by cyclic GMP formation. NS-7 concentration-dependently inhibited both the veratridine- and KCl-induced NOS activation with IC50 values of 9.3 and 9.6 microM, respectively. The reversal of KCl-evoked NOS activity by NS-7 was also observed under blockade of both ionotropic glutamate receptors and the Na+ channel with MK-801, 6-cyano-7-nitroquinoxaline-2,3-dione, and tetrodotoxin. In contrast, NS-7, even at 100 microM, did not affect N-methyl-D-aspartate-stimulated NOS activity, nor did it have any influence on NOS activity determined in the soluble fraction of rat hippocampus. Because NS-7 has already been shown to block both Na+ and Ca2+ channels, the present findings suggest that this compound inhibits depolarization-induced NOS activation by reducing Ca2+ influx through blockade of Na+ and Ca2+ channels in primary neuronal culture.
Tatsumi
S
S
Research Laboratories, Nippon Shinyaku Co., Ltd., Kyoto, Japan.
Itoh
Y
Y
Ma
F H
FH
Higashira
H
H
Ukai
Y
Y
Yoshikuni
Y
Y
Kimura
K
K
D000818:Animals; D002478:Cells, Cultured; D004594:Electrophysiology; D004789:Enzyme Activation; D006624:Hippocampus / Q000187:drug effects; D008297:Male; D051379:Mice / Q000196:embryology; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology*; D018696:Neuroprotective Agents / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014701:Veratridine / Q000494:pharmacology
C106144:4-(4-fluorophenyl)-2-methyl-6-(5-piperidinopentyloxy)pyrimidine hydrochloride; D018696:Neuroprotective Agents; D011743:Pyrimidines; D016202:N-Methylaspartate; D011189:Potassium Chloride; D014701:Veratridine; D019001:Nitric Oxide Synthase