nitroarginine has been researched along with selfotel* in 2 studies
2 other study(ies) available for nitroarginine and selfotel
| Article | Year |
|---|---|
The HIV-1 coat protein gp120 and some of its fragments potently activate native cerebral NMDA receptors mediating neuropeptide release.
The objective of this study was to investigate the effects of the HIV-1 envelope protein gp120 and its peptide fragments on the function of N-methyl-D-aspartate (NMDA) receptors mediating release of cholecystokinin (CCK) and somatostatin (SRIF). These are nonconventional NMDA receptors recently found to be activated by glycine or D-serine 'only'. The release of cholecystokinin-like immunoreactivity (CCK-LI) and of somatostatin-like immunoreactivity (SRIF-LI) elicited by 12 mM K+ from superfused rat neocortex synaptosomes was potently increased by gp120, its cyclic V3 loop and the linear V3 sequence BRU-C-34-A, but not by RP-135 (a central portion of BRU-C-34-A). The EC50 values of gp120 were 0.02 nM (CCK-LI release) and 0.01 nM (SRIF-LI release). The releasing effect of gp120 was prevented by blocking the glycine site or the ion channel of NMDA receptors, but not the glutamate recognition site; in addition, the gp120 effect was strongly inhibited by nanomolar concentrations of Zn2+ ions and by low micromolar concentrations of ifenprodil. It is concluded that gp120 acts as a very potent agonist at the glycine site of NMDA receptors sited on CCK- and SRIF-releasing nerve endings; the protein is able to activate the receptor channel in the absence of glutamate. Gp120 activates the receptors through its V3 loop as peptide fragments related to V3 retain near-maximal activity. The sensitivity of the gp120 effect to both Zn2+ and ifenprodil would not be incompatible with the idea that these NMDA receptors contain the triple subunit combination NR1/NR2A/NR2B. Topics: 2-Amino-5-phosphonovalerate; Animals; Cerebral Cortex; Cholecystokinin; Dizocilpine Maleate; Enzyme Inhibitors; Excitatory Amino Acid Antagonists; HIV Envelope Protein gp120; HIV-1; Indoles; Kynurenic Acid; Male; Maleimides; Neurons; Nitroarginine; Peptide Fragments; Pipecolic Acids; Piperazines; Piperidines; Potassium; Protein Structure, Tertiary; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Somatostatin; Synaptic Transmission; Synaptosomes; Zinc | 2000 |
The role of P-type calcium channels in the depolarization-induced activation of nitric oxide synthase in frontal cortex.
In this study we demonstrate that 50 mM K+ stimulates the conversion of L-[3H]arginine to L-[3H]citrulline and that this effect is blocked by 10 microM N omega-nitro-L-arginine, a nitric oxide synthase inhibitor, and Ca(2+)-free conditions. Amiloride (1 mM) and low Na+ conditions were used to test the possible involvement of the Na(+)-Ca2+ exchanger. These treatments were without effect. The calcium channel blockers 10 mM Mg2+, 100 microM Cd2+, and 10 mM Co2+ also blocked the K+ response, suggesting the involvement of voltage-dependent calcium channels (VDCCs). The specific VDCC involved seems to be the P type, as funnel-web spider toxin blocked the response whereas 200 microM Ni2+, 10 microM nifedipine, and 100 nM omega-conotoxin did not. Topics: Amiloride; Amino Acid Oxidoreductases; Analysis of Variance; Animals; Arginine; Calcium Channel Blockers; Calcium Channels; Carrier Proteins; Citrulline; Enzyme Activation; Frontal Lobe; In Vitro Techniques; Male; N-Methylaspartate; Nitric Oxide Synthase; Nitroarginine; omega-Conotoxins; Peptides; Pipecolic Acids; Polyamines; Potassium; Rats; Rats, Sprague-Dawley; Sodium-Calcium Exchanger | 1994 |