Participation of Intracellular Ca2+ Stores in Ca2+ Signalling in Neurons of the Thalamic Laterodorsal Nucleus of Rats
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- 作者：L. P. Shutov ; I. A. Kruglikov and N. V. Voitenko
- 关键词：thalamus ; interneuron ; thalamo ; cortical neuron ; intracellular Ca2+ concentration ; intracellular store ; Ca2+ signalling ; caffeine
- 刊名：Neurophysiology
- 出版时间：2001
- 出版年：2001
- 期刊代码：28_00902977
- 类别：en
- 卷：33
- 期：2
- 页码：94-97
- 数据来源：sp
摘要
Experiments were carried out on isolated neurons of the thalamic nucleus lateralis dorsalis (LD) from 12-day-old rats. According to the morphological characteristics, LD neurons were classified as relay thalamo-cortical units and interneurons. The concentration of free Ca2+ ions in the cytoplasm ([Ca2+]i) was measured by a fluorescent calcium indicator, fura-2AM. Application of 30 mM caffeine caused a transient change in the [Ca2+]i in 8 of 15 and in 6 of 11 of the thalamo-cortical units and interneurons under study, respectively. After stimulation of a cell with application of 50 mM KCl, a caffeine-induced increase in the [Ca2+]i was observed in all tested neurons. To study the contribution of Ca2+-induced Ca2+ release (CICR) to the calcium transient evoked by depolarization of the neuronal membrane, caffeine in a subthreshold concentration was pre-applied. After 50 mM KCl had been added to the medium following pre-application of 0.5 mM caffeine, the calcium transient amplitude in thalamo-cortical neurons increased by 51 ± 7%(n = 16). In interneurons this effect was not observed (n = 11). The data obtained allow us to hypothesize that CICR contributes to the depolarization-evoked calcium transient only in the relay (thalamo-cortical) neurons. Differences in the pattern of calcium signalling, which were detected in two types of neurons of the thalamic LD, can be a factor determining distinctions in the physiological characteristics of these neurons.