第61回日本生理学会(前橋)1984.3.

コイの終神経節細胞における過分極性電位

 コイの嗅球最吻側部の嗅神経層内側部には、終神経(Nervus terminalis)の神経節細胞(NT細胞)が存在する。今回、われわれは、嗅索および嗅神経の電気刺激に対するNT細胞の細胞内電位応答を調べた。NT細胞は、内側嗅索刺激に対して過分極応答を示したが、外側嗅索刺激には無応答であった。また、約70%のNT細胞は嗅神経刺激に対しても過分極応答を示した。これらの過分極応答は、1)潜時が長いこと、2)内側嗅索のくり返し刺激(0.5Hz以上)で増強を示さないことで、僧帽細胞に生じるIPSPと異なっていた。


HYPERPOLARIZING POTENTIALS IN THE GANGLION CELLS OF THE NERVUS TERMINALIS IN THE CARP.
FUJITA, I., SATOU, M. and UEDA, K.
Zool. Inst., Fac. Sci.,
Univ. Tokyo, Bunkyo-ku, Tokyo 113

In the carp, intracellular potentials were analyzed in the ganglion cells of the nervus terminalis (NT cells) following electrical shocks to the olfactory nerve (ON), medial (MOT) or lateral (LOT) olfactory tract. All the NT cell recordings showed long-lasting hyperpolarizing potentials after MOT shocks, but no response after LOT shocks. ON shocks also elicited long-lasting hyperpolarizing potentials in 76% of the NT cells. The hyperpolarizing potentials in the NT cells had different properties from IPSPs in mitral cells in the medial part of the olfactory bulb (mMC): 1) the MOT-evoked IPSPs in the mMC had two successive phases, while no such phases were observed in the MOT-evoked hyperpolarizing potentials in the NT cells, 2) repetitive MOT shocks at a frequency higher than 0.5 Hz caused potentiation of the IPSPs in the mMC, while the hyperpolarizing potentials in the NT cells were not potentiated by repetitive MOT shocks, and 3) the onset latencies of the MOT-evoked hyperpolarizing potentials in the NT cells were longer than those of the MOT-evoked IPSPs in the mMC.


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