Hillyard D R, Monje V D, Mintz I M, Bean B P, Nadasdi L, Ramachandran J, Miljanich G, Azimi-Zoonooz A, McIntosh J M, Cruz L J
Department of Biology, University of Utah, Salt Lake City 84132.
Neuron. 1992 Jul;9(1):69-77. doi: 10.1016/0896-6273(92)90221-x.
Voltage-sensitive Ca2+ channels that control neurotransmitter release are blocked by omega-conotoxin (omega-CgTx) GVIA from the marine snail Conus geographus, the most widely used inhibitor of neurotransmitter release. However, many mammalian synapses are omega-CgTx-GVIA insensitive. We describe a new Conus peptide, omega-CgTx-MVIIC, that is an effective inhibitor of omega-CgTx-GVIA-resistant synaptic transmission. Ca2+ channel targets that are inhibited by omega-CgTx-MVIIC but not by omega-CgTx-GVIA include those mediating depolarization-induced 45Ca2+ uptake in rat synaptosome preparations, "P" currents in cerebellar Purkinje cells, and a subset of omega-CgTx-GVIA-resistant currents in CA1 hippocampal pyramidal cells. The characterization of omega-CgTx-MVIIC by a combination of molecular genetics and chemical synthesis defines a general approach for obtaining ligands with novel receptor subtype specificity from Conus.
