Journal article
Caffeine-induced calcium release from internal stores in cultured rat sensory neurons
Neuroscience, Vol.57(3), pp.845-859
1993
DOI: 10.1016/0306-4522(93)90029-F
PMID: 8309540
Abstract
Free intracellular calcium concentration ([Ca2+]in) was recorded at 22 degrees C by means of Indo-1 or Fura-2 single-cell microfluorometry in cultured dorsal root ganglion neurons obtained from neonatal rats. The resting [Ca2+]in in dorsal root ganglion neurons was 73 +/- 21 nM (mean +/- S.D., n = 94). Fast application of 20 mM caffeine evoked [Ca2+]in transient which reached a peak of 269 +/- 64 nM within 5.9 +/- 1.1 s. After reaching the peak the [Ca2+]in level started to decline in the presence of caffeine and for 87.2 +/- 10.6 s cytoplasmic calcium returned to an initial resting value. In 40% of neurons tested [Ca2+]in decreased to subresting levels following the washout of caffeine (the so-called post-caffeine undershoot). On average, the undershoot level was 19 +/- 2.5 nM below the resting [Ca2+]in value. Prolonged exposure of caffeine depleted the caffeine-sensitive stores of releasable Ca2+; the degree of this depletion depended on caffeine concentration. The depletion of the caffeine-sensitive internal stores to some extent was linked to calcium extrusion via La(3+)-sensitive plasmalemmal Ca(2+)-ATPases. The stores could be partially refilled by the uptake of cytoplasmic Ca2+, but the complete recovery of releasable Ca2+ content of the caffeine-sensitive pools required the additional calcium entry via voltage-operated calcium channels. Caffeine-evoked [Ca2+]in transients were effectively blocked by 10 microM ryanodine, 5 mM procaine, 10 microM dantrolene or 0.5 mM Ba2+, thus sharing the basic properties of the Ca(2+)-induced-Ca2+ release from endoplasmic reticulum. Pharmacological manipulation with caffeine-sensitive stores interfered with the depolarization-induced [Ca2+]in transients. In the presence of low caffeine concentration (0.5-1 mM) in the extracellular solution the rate of rise of the depolarization-triggered [Ca2+]in transients significantly increased (by a factor 2.15 +/- 0.29) suggesting the occurrence of Ca(2+)-induced Ca2+ release. When the caffeine-sensitive stores were emptied by prolonged application of caffeine, the amplitude and the rate of rise of the depolarization-induced [Ca2+]in transients were decreased. These facts suggest the involvement of internal caffeine-sensitive calcium stores in the generation of calcium signal in sensory neurons.
Details
- Title: Subtitle
- Caffeine-induced calcium release from internal stores in cultured rat sensory neurons
- Creators
- Y USACHEV - Bogomoletz inst. physiology, Kiev 252601, UkraineA SHMIGOL - Bogomoletz inst. physiology, Kiev 252601, UkraineN PRONCHUK - Bogomoletz inst. physiology, Kiev 252601, UkraineP KOSTYUK - Bogomoletz inst. physiology, Kiev 252601, UkraineA VERKHRATSKY - Bogomoletz inst. physiology, Kiev 252601, Ukraine
- Resource Type
- Journal article
- Publication Details
- Neuroscience, Vol.57(3), pp.845-859
- Publisher
- Elsevier; Oxford
- DOI
- 10.1016/0306-4522(93)90029-F
- PMID
- 8309540
- ISSN
- 0306-4522
- eISSN
- 1873-7544
- Language
- English
- Date published
- 1993
- Academic Unit
- Iowa Neuroscience Institute; Anesthesia; Fraternal Order of Eagles Diabetes Research Center; Neuroscience and Pharmacology
- Record Identifier
- 9984040207002771
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