A voltage-clamp study of calcium currents in neurons freshly isolated from the dorsal root ganglion of adult rats.
Calcium currents were studied in a preparation of freshly isolated neurons of the dorsal root ganglion (DRG) of adult rats using the whole-cell voltage-clamp technique in conditions of minimal current flow through sodium and potassium channels. A low-threshold (LT) and a high-threshold (HT) current were distinguished on the basis of a different potential of activation. Both currents also showed differences in their peak amplitude, their distribution among the cells, their kinetics, their steady-state inactivation curve and their sensitivity to cadmium. Comparison of the properties of both currents with the known properties of calcium currents in DRG neurons from immature animals indicates a slower rate of inactivation of the LT-current in the adult DRG neuron. The calcium entry blocker flunarizine (10 microM) caused a negative shift of the steady-state inactivation curve of the inactivating component of HT-current, an effect which suggests voltage-dependent inhibition.
Leybaert
L
L
Laboratorium voor Normale en Pathologische Fysiologie, Universiteit Gent, Belgium.
de Hemptinne
A
A
D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology*; D004553:Electric Conductivity; D005444:Flunarizine / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000166:cytology*; D007700:Kinetics; D009474:Neurons / Q000502:physiology*; D009543:Nifedipine / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000502:physiology
D015220:Calcium Channels; D015221:Potassium Channels; D015222:Sodium Channels; D002104:Cadmium; D009543:Nifedipine; D005444:Flunarizine