Neuropharmacology Poster Session
Zhang, YX (Beijing Institute of Pharmacology and Toxicology, Beijing, China)
Zheng, JQ (Beijing Institute of Pharmacology and Toxicology, Beijing, China)
Zhou, JH (Beijing Institute of Pharmacology and Toxicology, Beijing, China)
A large amount of research demonstrated that glucocorticoids had potent effect on the central nervous system, especially on the hippocampus. In our present paper, effect of corticosterone (CORT) on the hippocampal synaptic plasticity as well as voltage-dependent calcium (VOC) channel on the membrane of hippocampal neurons was investigated. Administration of CORT (ip, 1 mg/kg, 4 mg/kg and 10 mg/kg) had a trend to increase the basal amplitude of population spike without significance while it dose- dependently inhibited the formation of long-term potentiation (LTP) in hippocampal dentate gyrus induced by a tetanic stimulation (60 Hz, 30 pulses), suggesting that CORT might impair the synaptic plasticity and inhibit the synaptic transmission in hippocampus. Whole-cell recording experiment showed that CORT (10-6 M, 10-5 M and 10-4 M) sprayed on the surface of hippocampal neurons instantly dose-dependently increased the Ca2+ current with nearly 60 % of elevation of Ca2+ current induced by the highest concentration of CORT. CORT (10-4 M) sprayed on the membrane of hippocampal neurons significantly shortened the interval between two synaptic currents from 498 ms to 114 ms and augmented the frequency of synaptic currents from 3 Hz to 13 Hz. The present result suggested that CORT could increase the synaptic activity. However, this result was contradictory, to some extent, to the CORT-induced inhibition of LTP formation in hippcampus. The further study is being undertaken.
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|Zhou, JZ; Zhang, YX; Zheng, JQ; Zhou, JH; (1998). Effect of Corticosterone on Hippocampal Synaptic Plasticity and Voltage-dependent Calcium Channel on the Membrane of Hippocampal Neurons. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Available at URL http://www.mcmaster.ca/inabis98/neuropharm/zhou0107/index.html|
|© 1998 Author(s) Hold Copyright|