ABSTRACT
MACHKO MATSUMOTO], HIROKO TOGASHIK*, TAKU KOJIMA2, KAORITACHIBANA2, SATOSHI OHASHI! and MITSUHIRO YOSHIOKAx 1 Department of Pharmacology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, Sapporo 060-8638, Japan
INTRODUCTION The hippocampus is known to be an important structure for the expression of fear and anxiety, and emotional memory processing. The hippocampal formation consists of three principal fields that are connected as the trisynaptic input pathway,
namely, the entorhinal cortex to dentate gyms granule cells, mossy fiber to CA3, and Schaffer collateral to CA1 pyramidal cells. Numerous in vitro studies have reported that the electrophysiological properties such as input resistance (Beck et al, 1992), receptor-effector pathways (Okuhara and Beck, 1994) and the mechanism of longterm potentiation (LTP) (Weisskopf et al, 1994; Villacres et al, 1998) are different between the CA1 and CA3 pyramidal cells.
