Summary
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1.
The effects of strychnine on the voltage-dependent Ca2+ current (I Ca) were studied in physically isolatedAplysia neurons and enzymatically dissociated frog sensory neurons of the dorsal root ganglion. Neurons were studied under the internal perfusion and the voltage clamp condition.
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2.
Strychnine decreased theI Ca with threshold concentrations for effect at 1 to 10µM. The depression ofI Ca increased with strychnine dose without effects on the current-voltage relation ofI Ca. The effects of low concentrations of strychnine were reversible, but recovery was incomplete at higher concentrations. The potency of strychnine was about 10 times less than that of diltiazem, an organic Ca2+ antagonist. At 100µM theI Ca ofAplysia neurons was reduced to about half of the control. This concentration of strychnine also reduced the peak amplitude ofI Ca of frog sensory neurons.
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3.
These results indicate that, in addition to its actions on transmitter responses and on Na+ and K+ currents, strychnine has effects onI Ca that have not previously been appreciated.
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Oyama, Y., Akaike, N. & Carpenter, D.O. Strychnine decreases the voltage-dependent Ca2+ current of bothAplysia and frog ganglion neurons. Cell Mol Neurobiol 8, 307–314 (1988). https://doi.org/10.1007/BF00711172
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DOI: https://doi.org/10.1007/BF00711172