The Inhibitory
Effects of Dantrolene on Action Potential-Induced
Calcium Transients in Cultured Rat Dorsal Root
Ganglion Neurons
A.
AYAR, H. KELESTIMUR1
Department of Obstetrics and Gynaecology, and 1Department
of Pharmacology, Faculty of Medicine, Firat
University, Elazig, Turkey
Received May 29, 2001
Accepted November 19, 2001
Summary
We investigated the actions of
dantrolene Ca2+-induced on Ca2+-release
(CICR) evoked by action potentials in cultured
rat sensory neurons. The effect of dantrolene on
action potential after-depolarization and
voltage-activated calcium currents was studied in
cultured neonatal rat dorsal root ganglion cells
(DRG) using the whole-cell patch-clamp technique.
Depolarizing current injection evoked action
potentials and depolarizing after-potentials,
which are activated as a result of CICR following
a single action potential in some cells. The type
of after-potentials was determined by inducing
action potentials from the resting membrane
potential. Extracellular application of
dantrolene (10 mM) abolished
after-depolarizations without affecting action
potential properties. Furthermore, dantrolene
significantly reduced repetitive action
potentials after depolarizing current injection
into these neurons, but had no significant effect
on the steady-state current voltage relationship
of calcium currents in these neurons. We conclude
that dantrolene inhibits the induction of action
potential after depolarizations by inhibiting
CICR in cultured rat sensory neurons.
Key
words
Dantrolene
· CICR · Action potential
after-potentials · Cultured sensory
neurons · Patch clamp
Reprint
requests
Dr. Ahmet AYAR, Firat University, Faculty of
Medicine (TIP FAK), Department of Pharmacology,
Tr-23119, Elazig, Turkey, Fax: + 90 424 237 91
38, e-mail: aayar@firat.edu.tr
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