Calcium-activated currents in cultured neurones from rat dorsal root ganglia.

Currie KP, Scott RH
Br J Pharmacol. 1992 106 (3): 593-602

PMID: 1324075 · PMCID: PMC1907550 · DOI:10.1111/j.1476-5381.1992.tb14381.x

1. Voltage-activated Ca2+ currents and caffeine (1 to 10 mM) were used to increase intracellular Ca2+ in rat cultured dorsal root ganglia (DRG) neurones. Elevation of intracellular Ca2+ resulted in activation of inward currents which were attenuated by increasing the Ca2+ buffering capacity of cells by raising the concentration of EGTA in the patch solution to 10 mM. Low and high voltage-activated Ca2+ currents gave rise to Cl- tail currents in cells loaded with CsCl patch solution. Outward Ca2+ channel currents activated at very depolarized potentials (Vc + 60 mV to + 100 mV) also activated Cl- tail currents, which were enhanced when extracellular Ca2+ was elevated from 2 mM to 4 mM. 2. The Ca(2+)-activated Cl- tail currents were identified by estimation of tail current reversal potential by use of a double pulse protocol and by sensitivity to the Cl- channel blocker 5-nitro 2-(3-phenyl-propylamino) benzoic acid (NPPB) applied at a concentration of 10 microM. 3. Cells loaded with Cs acetate patch solution and bathed in medium containing 4 mM Ca2+ also had prolonged Ca(2+)-dependent tail currents, however these smaller tail currents were insensitive to NPPB. Release of Ca2+ from intracellular stores by caffeine gave rise to sustained inward currents in cells loaded with Cs acetate. Both Ca(2+)-activated tail currents and caffeine-induced inward currents recorded from cells loaded with Cs acetate were attenuated by Tris based recording media, and had reversal potentials positive to 0 mV suggesting activity of Ca(2+)-activated cation channels.4. Our data may reflect (a) different degrees of association between Ca2+-activated channels with voltage-gated Ca2+ channels, (b) distinct relationships between channels and intracellular Ca2" stores and Ca2+ homeostatic mechanisms, (c) regulation of Ca2+-activated channels by second messengers, and (d) varying channel sensitivity to Ca2 , in the cell body of DRG neurones.

MeSH Terms (11)

Action Potentials Animals Caffeine Calcium Calcium Channels Cells, Cultured Electrodes Electrophysiology Ganglia, Spinal Neurons Rats

Connections (1)

This publication is referenced by other Labnodes entities:

Links