Novel omega-conopeptides reduced field potential amplitudes in the rat hippocampal slice.
The synthetic omega-conopeptides SNX-111 (MVIIA), SNX-124 (GVIA), SNX-183 (SVIB), and SNX-185 (TVIA) reduced excitatory postsynaptic potential (EPSP) amplitudes measured in the stratum radiatum of rat hippocampal slices by about 50% at doses at or near 200 nM. These effects were at least partially reversible in most slices. EPSP amplitude was not further reduced at the highest concentrations of SNX-111, SNX-124, and SNX-185 (1.5-10 microM). In contrast, the highest concentrations of SNX-183 (2 and 10 microM) further reduced EPSP amplitude to about 20% of control. SNX-183 reduced EPSP amplitude in slices previously treated with maximally effective doses of SNX-111 or SNX-124. These results suggest that there are at least two classes of omega-conopeptide receptor sites that modulate neurotransmitter release in the rat hippocampus.
Neurex Corporation, Menlo Park, CA 94025.
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Fox
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009479:Neuropeptides / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism; D020866:omega-Conotoxin GVIA; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D009479:Neuropeptides; D010455:Peptides; D020960:omega-Conotoxins; C087968:omega-conotoxin TVIA; C077380:omega-conotoxin SVIB; C078452:ziconotide; D020866:omega-Conotoxin GVIA