Mecamylamine is a selective non-competitive antagonist of N-methyl-D-aspartate- and aspartate-induced currents in horizontal cells dissociated from the catfish retina.
The nicotinic acetylcholine channel blockers mecamylamine (MECA) and pempidine (PEMP) blocked voltage-clamped isolated catfish retina cone horizontal responses to aspartate (Asp) and N-methyl-D-aspartate (NMDA) but had little effect on currents induced by kainate and quisqualate. Concentration response curves for NMDA and Asp in the presence of MECA suggested that MECA was a non-competitive inhibitor of NMDA and Asp responses. Further, the MECA and PEMP block of NMDA and Asp-induced currents was highly voltage-sensitive. The non-competitive and voltage-sensitive block of NMDA and Asp-induced currents by MECA suggest that MECA (and PEMP) block the NMDA receptor ion channel.
O'Dell
T J
TJ
Neuroscience Graduate Program, Marine Biomedical Institute, University of Texas Medical Branch, Galveston 77550.
Christensen
B N
BN
D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D002397:Catfishes; D004553:Electric Conductivity; D066298:In Vitro Techniques; D008464:Mecamylamine / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D016202:N-Methylaspartate; D012160:Retina / Q000187:drug effects / Q000502:physiology*
D001224:Aspartic Acid; D016202:N-Methylaspartate; D008464:Mecamylamine