Elementary properties and pharmacological sensitivities of calcium channels in mammalian peripheral neurons

• Published in: Neuron (Cambridge, Mass.) Vol. 2; no. 5; pp. 1453 - 1463
• Main Authors: Plummer, Mark R., Logothetis, Diomedes E., Hess, Peter
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.1989
• Subjects: Acetylcholine - pharmacology; Animals; Calcium - metabolism; Calcium Channels - drug effects; Calcium Channels - physiology; Dihydropyridines - pharmacology; GTP-Binding Proteins - metabolism; Guanosine 5'-O-(3-Thiotriphosphate); Guanosine Triphosphate - analogs & derivatives; Guanosine Triphosphate - pharmacology; Ion Channel Gating - drug effects; Mollusk Venoms - pharmacology; Neurons - metabolism; omega-Conotoxins; Pheochromocytoma - pathology; Rats; Thionucleotides - pharmacology; Tumor Cells, Cultured - metabolism
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/0896-6273(89)90191-8

The major component of whole-cell Ca 2+ current in differentiated, neuron-like rat pheochromocytoma (PC12) cells and sympathetic neurons is carried by dihydropyridine-insensitive, high-threshold-activated N-type Ca 2+ channels. We show that these channels have unitary properties distinct from those of previously described Ca 2+ channels and contribute both slowly inactivating and large sustained components of whole-cell current. The N-type Ca 2+ currents are modulated by GTP binding proteins. The snail toxin ω-conotoxin reveals two pharmacological components of N-type currents, one blocked irreversibly and one inhibited reversibly. Contrary to previous reports, neuronal L-type channels are insensitive to ω-conotoxin. N-type Ca 2+ channels appear to be specific for neuronal cells, since their functional expression is greatly enhanced by nerve growth factor.