Action of Ca2+ agonists/antagonists in mammalian peripheral neurons.
The action of several ligands on the low- (LVA,T) and high-threshold (HVA,L and N) Ca channels of adult rat sensory neurons and human neuroblastoma IMR32 cells has been investigated. In both cell types, 40 microM Cd2+ and 6.4 microM /omega-Conotoxin (omega-CgTx) selectively blocked the HVA channels, sparing the majority of LVA channels that were antagonized by amiloride and Ni2+. In 50% of the cells, however, /omega-CgTx spared also a 15% of HVA channels that proved to be sensitive to BAY K 8644. The agonistic action of BAY K 8644 on [omega-CgTx-resistant HVA channels caused a large Ba current increase, prolonged current deactivation and acceleration of HVA channels inactivation that was particularly evident in adult rat DRG.
Carbone
E
E
Dept. Anatomy and Human Physiology, Torino, Milano, Italy.
Clementi
F
F
Formenti
A
A
Pollo
A
A
Sher
E
E
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D009447:Neuroblastoma; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D010525:Peripheral Nerves / Q000187:drug effects / Q000502:physiology*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000502:physiology
D002121:Calcium Channel Blockers; D015220:Calcium Channels