[3H]L-arginine transport and nitric oxide synthase activity in foetal hypothalamic cultures.
[3H]L-arginine uptake and the conversion of [3H]L-arginine to [3H]citrulline were characterized in foetal hypothalamic cultures. [3H]L-arginine uptake was reduced by L-ornithine (10 microM-1 mM), high extracellular K+ (56 mM), L-glutamate (100 microM) and removal of extracellular Ca2+, but was increased by the nitric oxide synthase inhibitor, Nw-nitro-L-arginine benzyl ester (L-NABE; 1 mM). [3H]citrulline formation was inhibited by L-NABE (1 mM), increased by high extracellular K+ (56 mM) and unaffected by L-glutamate (100 microM). Removal of extracellular Ca2+ reduced [3H]citrulline formation by mixed (neurones and glia) and neurone-enriched cultures but not by glial-enriched cells. The results suggest that [3H]L-arginine uptake into hypothalamic cultures is mediated by the system y+ transporter and is dependent on extracellular Ca2+. [3H]citrulline production in hypothalamic neuronal, but not glial, cells is also dependent on extracellular Ca2+.
Wayte
J
J
Department of Pharmacology, Charing Cross & Westminster Medical School, London, UK.
Buckingham
J C
JC
Cowell
A M
AM
D026905:Amino Acid Transport Systems; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D002956:Citrulline / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007031:Hypothalamus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009457:Neuroglia / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009952:Ornithine / Q000378:metabolism; D051381:Rats
D026905:Amino Acid Transport Systems; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D002956:Citrulline; C071057:N(w)-nitroarginine benzyl ester; D001120:Arginine; D009952:Ornithine; D019001:Nitric Oxide Synthase