Jpn. J. Pharmacol. 84 (2), 179-187 (2000)

Involvement of Complexin╩II in Synaptic Plasticity in the CA1 Region of the Hippocampus: The Use of Complexin╩II-Lacking Mice

Guang-Zhe Huang1, Hisamitsu Ujihara1,*, Sei-ichi Takahashi2,4, Hideto Kaba2,4, Takeshi Yagi3 and Shinpei Inoue1

Departments of 1Neuropsychiatry and 2Physiology, Kochi Medical School, Nankoku, Kochi 783-8505, Japan
3Laboratory of Neurobiology, National Institute for Physiological Sciences, Myodaiji, Okazaki, Aichi 444-8585, Japan
4CREST, Japan Science & Technology Corporation
*Corresponding author.╩╩FAX:+81-88-880-2360

Abstract: An electrophysiological study was performed with mice lacking complexin╩II, a presynaptic protein. The long-term potentiation (LTP) by high-frequency stimulation, recorded in the hippocampal CA1 area, was decreased in complexin╩II-lacking mice (CPXII KO mice). The overall postsynaptic currents elicited by low frequency stimulation on the Schaffer collateral/commissural fibers in the hippocampal CA1 pyramidal cells were not different between wild-type and mutant mice. Excitatory postsynaptic currents (EPSCs) recorded in the presence of 50╩mM bicuculline and inhibitory postsynaptic currents (IPSCs) recorded in the presence of 50╩mM AP-5 (DL-2-amino-5-phosphonopentanoic acid) +╩30╩mM CNQX (6-cyano-7-nitroquinoxaline-2,3-dione) were also identical between wild-types and mutants. Furthermore, the EPSCs following repetitive stimulation (10╩Hz) in CPXII KO mice did not show any difference with wild-types. These findings suggest that complexin╩II does not play a crucial role in ordinary neural transmission, short-term synaptic plasticity or synaptic transmission during high-frequency repetitive stimulation. Therefore, the protein is thought to be involved in the LTP process following tetanic stimulation, including the induction and /or maintenance of the LTP.

Keywords: Complexin╩II-lacking mice, Long-term potentiation, Hippocampus, CA1 pyramidal cell, Whole-cell recording

Copyrightę The Japanese Pharmacological Society 2000

[Back to TOC]