Elementary properties and pharmacological sensitivities of calcium channels in mammalian peripheral neurons |
| |
Authors: | M R Plummer D E Logothetis P Hess |
| |
Institution: | Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, Massachusetts 02115. |
| |
Abstract: | The major component of whole-cell Ca2+ current in differentiated, neuron-like rat pheochromocytoma (PC12) cells and sympathetic neurons is carried by dihydropyridine-insensitive, high-threshold-activated N-type Ca2+ channels. We show that these channels have unitary properties distinct from those of previously described Ca2+ channels and contribute both slowly inactivating and large sustained components of whole-cell current. The N-type Ca2+ currents are modulated by GTP binding proteins. The snail toxin omega-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 omega-conotoxin. N-type Ca2+ channels appear to be specific for neuronal cells, since their functional expression is greatly enhanced by nerve growth factor. |
| |
Keywords: | |
|
|