Ca2+ channels in rat central and peripheral neurons: high-threshold current resistant to dihydropyridine blockers and omega-conotoxin

Neuron. 1991 Feb;6(2):269-80. doi: 10.1016/0896-6273(91)90362-4.


Block of Ca2+ channel current by dihydropyridines and by omega-conotoxin (omega-CgTx) was studied in a variety of freshly dissociated rat neurons. In most neurons, including those from dorsal root ganglia, sympathetic ganglia, spinal cord, cerebral cortex, and hippocampus, nitrendipine and omega-CgTx each blocked a fraction of the high-threshold current, but a substantial fraction of current remained even when the two blockers were applied together at saturating concentrations. An extreme case was cerebellar Purkinje neurons, in which very little current was blocked by either nitrendipine or omega-CgTx. These results demonstrate the existence in mammalian neurons of high-threshold channels that are resistant to both omega-CgTx and dihydropyridine blockers. Such channels might underlie instances of synaptic transmission and other processes that depend on Ca2+ entry but are not sensitive to these blockers.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / drug effects
  • Calcium Channels / metabolism*
  • Calcium Channels / physiology
  • Central Nervous System / cytology
  • Central Nervous System / metabolism*
  • Differential Threshold
  • Dihydropyridines / pharmacology*
  • Drug Resistance
  • Electrophysiology
  • Kinetics
  • Neurons / metabolism*
  • Nitrendipine / pharmacology
  • Osmolar Concentration
  • Peptides, Cyclic / pharmacology*
  • Peripheral Nerves / cytology
  • Peripheral Nerves / metabolism*
  • Rats
  • omega-Conotoxin GVIA


  • Calcium Channel Blockers
  • Calcium Channels
  • Dihydropyridines
  • Peptides, Cyclic
  • 1,4-dihydropyridine
  • omega-Conotoxin GVIA
  • Nitrendipine