Voltage-dependent facilitation of calcium channels in rat neostriatal neurons

J Neurophysiol. 1996 Oct;76(4):2290-306. doi: 10.1152/jn.1996.76.4.2290.


1. Voltage-dependent facilitation of Ca2+ channels was studied in acutely isolated adult rat neostriatal neurons. Particular attention was paid to the facilitation of L-type channels. 2. In the absence of neuromodulators, the current-voltage relationship for whole cell Ba2+ currents was enhanced by a prepulse to +100 mV. The median enhancement at -20 mV was nearly 60%. The voltage dependence and kinetics of the processes underlying the facilitation were similar to those reported in other neurons. N-, P-, Q-, and L-type currents contributed to the observed facilitation. 3. Voltage-dependent facilitation of L-type currents was studied by subtracting nifedipine-insensitive currents from control currents. Although the kinetics were similar to those of the whole cell currents, the half-activation voltage for facilitation of L-type currents [half-activation voltage (Vh) = -0.6 mV, slope factors (Vc) = 11.8 mV, [n = 5] was significantly less depolarized than that of the pooled currents (Vh = 47.3 mV, Vc = 12.3 mV, n = 7). 4. Repetitive depolarization with spikelike waveforms was also able to induce facilitation of L-type currents, suggesting that facilitation was not simply a consequence of a modal shift in gating like that induced by Bay K 8644. 6. Combined whole cell recording and single-cell reverse transcription-polymerase chain reaction amplification revealed that neostriatal medium spiny neurons expressed detectable levels of either class C or class D L-type channel alpha 1, subunit mRNA. Both neurons expressing class C L-type channels and neurons expressing class D L-type channels exhibited voltage-dependent facilitation.

Publication types

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

MeSH terms

  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / pharmacology
  • Animals
  • Barium / physiology*
  • Calcium Channel Agonists / pharmacology
  • Calcium Channels / physiology*
  • Ion Channel Gating
  • Ion Channels / physiology*
  • Kinetics
  • Membrane Potentials / physiology
  • Neostriatum / cytology
  • Neostriatum / physiology*
  • Neurons / physiology*
  • Nonlinear Dynamics
  • Patch-Clamp Techniques
  • Polymerase Chain Reaction / methods
  • Rats
  • Transcription, Genetic


  • Calcium Channel Agonists
  • Calcium Channels
  • Ion Channels
  • Barium
  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester