Inhibition of glutamate uptake and proton pumping in synaptic vesicles by S-nitrosylation.
Nitric oxide (NO; including NO-., NO+, and NO-) was found to inhibit glutamate uptake by isolated synaptic vesicles of rat brain. This was observed when two unrelated NO donors, S-nitrosogluthathione and S-nitroso-N-acetylpenicillamine, were used. The primary target of NO is the H(+)-ATPase found in the synaptic vesicles, which leads to dissipation of the electrochemical proton gradient and inhibition of glutamate uptake. Oxyhemoglobin (12 microM) and, to a much lesser extent, methemoglobin protected the vacuolar H(+)-ATPase from inhibition. Inhibition of H+ pumping by NO was reversed by addition of 0.5 mM dithiothreitol. The results indicate that the vacuolar H(+)-ATPase from synaptic vesicles is inhibited by NO by a mechanism that involves S-nitrosylation of critical sulfhydryl groups in the enzyme. The interaction of NO with synaptic vesicles might be of importance for the understanding of the multiple effects of NO in neuro-transmission.
Wolosker
H
H
Departmento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Brazil.
Reis
M
M
Assreuy
J
J
de Meis
L
L
D000818:Animals; D018691:Excitatory Amino Acid Antagonists; D008297:Male; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology; D009603:Nitroso Compounds / Q000378:metabolism / Q000494:pharmacology*; D010084:Oxidation-Reduction; D054328:Proton Pump Inhibitors; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013572:Synaptic Vesicles / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology
D018691:Excitatory Amino Acid Antagonists; D009603:Nitroso Compounds; D054328:Proton Pump Inhibitors; D013438:Sulfhydryl Compounds; D009569:Nitric Oxide; D006180:Proton-Translocating ATPases