| Autor: |
Shutov, L., Kruglikov, I., Voitenko, N. |
| Zdroj: |
Neurophysiology; Mar2001, Vol. 33 Issue 2, p94-97, 4p |
| Abstrakt: |
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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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