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Two oscillatory patterns induced by depolarization in tectal neurons of Xenopus

TSAI Hao-Jan, Li Lin, ZHU Dan, WANG HONG

Central Laboratory of the First Hospital, Peking University, Beijing 100034, China； Department of Ophthalmology of the First Hospital, Medical College of Inner Mongolia, Huhehaote 010050, China

Abstract

In the present study, we used in vitro whole-cell patch-clamp technique to record and analyze oscillatory activity of neurons
in the optic tectum of Xenopus. Two patterns of subthreshold oscillations were induced by long-term depolarizing current pulses. One
of the oscillating patterns occurred without a slow inward current (SIC); the other was superimposed on the SIC. The subthreshold
oscillations were induced by depolarization in 48% of the recorded neurons. Both the oscillations and the SIC were tetrodotoxin
(TTX)-resistant, but neither occurred when the slices were immersed in Ca2+ free solutions. The evocation of the oscillations was
voltage-sensitive: only when the initial membrane potentials of the neurons were held at -40 mV or -50 mV, 10 mV depolarization could
induce the subthreshold oscillations. The amplitude and duration of the SIC depended on the level of the initial membrane potential. The
subthreshold oscillations might play an important role in the physiological and behavioral functions of frogs, e.g. pattern discrimination,
prey recognition, avoiding behavior etc., furthermore, these oscillations might play roles in the integration of neural activity in both
mammals and non-mammalian vertebrates.

Key words: oscillations; slow inward current; depolarization; patch-clamp; tectal neurons; Xenopus

Received: 2008-08-04　　Accepted: 2008-10-31

Corresponding author: 蔡浩然　　E-mail: hjtsai@bjmu.edu.cn

Citing This Article：

TSAI Hao-Jan, Li Lin, ZHU Dan, WANG HONG. Two oscillatory patterns induced by depolarization in tectal neurons of Xenopus. Acta Physiol Sin 2009; 61 (1): 85-93 (in Chinese with English abstract).