Voltage-activated calcium channel currents of rat dorsal root ganglion cells are reduced by trimethyl lead.
Using the conventional whole-cell patch-clamp recording technique with cultured neurones of rat dorsal root ganglions (DRG), we analysed the effects of trimethyl lead (TML) on voltage-activated calcium channel currents. TML reduces voltage-activated calcium channel currents in a dose-dependent manner, with a threshold concentration below 0.5 microM and a total reduction of the current ( > or =80% of the control current) at concentrations above 50 microM. Half of the current is abolished at TML concentrations between 1 and 5 microM. The action is irreversible and is not voltage dependent. After application of TML the current decreases with each activation of the channel until a steady state is reached after 8-12 min, when the channel was activated every 10 s. The channel had to be in the open state for TML to act. TML is a potent compound for reducing voltage activated calcium channel currents. These effects of TML must be taken into account in explaining the neurotoxic effects of this organic metal compound.
Gawrisch
E
E
Georg-August Universität, Neuro- and Sinnesphysiologie, Göttingen, Germany.
Leonhardt
R
R
Büsselberg
D
D
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D013756:Tetraethyl Lead / Q000031:analogs & derivatives* / Q000633:toxicity
D015220:Calcium Channels; D013756:Tetraethyl Lead; C039474:trimethyllead