title: Effects of synthetic omega-conotoxin GVIA (omega-CgTX GVIA) on the membrane calcium current of an identifiable giant neurone, d-RPLN, of an African giant snail (Achatina fulica Ferussac), measured under the voltage clamp condition.
abstract: 1. The sodium and the calcium inward currents (INa and ICa) of an identifiable giant neurone, d-RPLN (dorsal-right parietal large neurone), of an African giant snail (Achatina fulica Férussac), were measured separately under the voltage clamp condition. 2. The effects of synthetic omega-conotoxin GVIA (omega-CgTX GVIA) on the calcium current of the neuromembrane were examined. 3. omega-CgTX GVIA is a peptide venom originally isolated from a fish-hunting marine snail (Conus geographus L.); the peptide venom has been demonstrated to block markedly calcium channels in vertebrates. 4. In the case of the d-RPLN membrane, the ICa was much larger than INa. The command voltage (Vc) to get the ICa in maximum was about 0 mV; the maximum value of ICa in a representative experimental case, was measured as approximately 0.8 microA. 5. With respect to the ICa of a molluscan giant neurone, d-RPLN, synthetic omega-CgTX GVIA at a high concentration, 5 X 10(-5) M, showed almost no effect, in spite of reporting the peptide venom affecting the ICa in vertebrate preparations.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D008978:Mollusk Venoms / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D012908:Snails; D012964:Sodium / Q000378:metabolism; D013997:Time Factors; D020866:omega-Conotoxin GVIA
chemical_list: D007473:Ion Channels; D008978:Mollusk Venoms; D020866:omega-Conotoxin GVIA; D012964:Sodium; D002118:Calcium