In:
Acta Anaesthesiologica Scandinavica, Wiley, Vol. 50, No. 6 ( 2006-07), p. 742-748
Abstract:
Background: Spontaneous Ca 2+ ‐oscillations are a possible mechanism of Ca 2+ ‐mediated signal transduction in neurons. They develop by a periodical interplay of Ca 2+ , which enters the neuron from the extracellular medium and triggers Ca 2+ release from the endoplasmic reticulum (ER). Ca 2+ ‐oscillations are terminated by reuptake into the ER or plasmalemmal extrusion. Spontaneous Ca 2+ ‐oscillations are glutamate dependent and appear to be responsible for neuronal plasticity and integration of information. Here, we examined the role of the gamma‐aminobutyric acid (GABA A ) receptor on spontaneous Ca 2+ ‐oscillations and studied the effects of the anaesthetics midazolam, thiopental and the non‐anesthetic barbituric acid on spontaneous Ca 2+ ‐oscillations. Methods: Hippocampal neuronal cell cultures of 19‐day‐old embryonic Wistar rats 17–18 days in culture were loaded with the Ca 2+ ‐sensitive dye Fura‐2AM. Experiments were performed using dual wave‐length excitation fluorescence microscopy and calibration constants were obtained from in situ calibration. Results: Spontaneous Ca 2+ ‐oscillations are influenced by the GABA A receptor. The intravenous anaesthetics midazolam and thiopental suppressed the amplitude and frequency reversibly in a dose‐dependent manner with EC 50 in clinically relevant concentrations. This effect was mediated via the GABA A receptor as it could be reversed by the GABA A receptor antagonist bicuculline. In contrast, the application of barbituric acid had no effects on the spontaneous Ca 2+ ‐oscillations. Conclusion: Spontaneous Ca 2+ ‐oscillations are influenced by the GABA A receptor. Spontaneous Ca 2+ ‐oscillations might represent an interesting model system to study anaesthetic mechanisms on neuronal information processing.
Type of Medium:
Online Resource
ISSN:
0001-5172
,
1399-6576
DOI:
10.1111/aas.2006.50.issue-6
DOI:
10.1111/j.1399-6576.2006.01031.x
Language:
English
Publisher:
Wiley
Publication Date:
2006
detail.hit.zdb_id:
2004319-3
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