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Published on: July 17, 2011
Agmatine blocked voltage-gated calcium channel in cultured rat hippocampal neurons
Xie-Chuan Weng1, Xiao-Dan Gai, Jian-Quan Zheng
1Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
Aim:
To investigate the mechanism of agmatine by observing the effect of agmatine on the voltage-gated channels in rat hippocampal neurons.
Methods:
The whole-cell patch recording technique was performed to record the voltage-gated potassium, sodium, and calcium currents in cultured rat hippocampus. Agmatine was applied directly to the single neuron using a pressure injector with microtubules.
Results:
Agmatine (500 micromol/L) had no significant effect on the voltage-gated potassium and sodium channels. Agmatine reversibly blocked the voltage-gated calcium channel and the blockade was enhanced with the increasing concentration of agmatine. The inhibitory rates were 21%+/-4%, 35%+/-6%, 49%+/-6%, 67%+/-4%, 69%+/-6%, 86%+/-8%, and 87%+/- 9%, at the concentration of 0.1, 0.5, 1.0, 5.0, 10.0, 50.0, and 100 micromol/L, respectively. IC50 was (1.2+/-0.4) micromol/L. Two-way ANOVA revealed that change of membrane potential displayed a significant interaction with the blockade by agmatine.
Conclusion:
Agmatine reversibly blocked the voltage-gated calcium channel in rat hippocampal neurons in a concentration- and voltage-dependent way. Agmatine might perform its physiological and pharmacological effects partially by blocking the calcium channel.
