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Hemispheric asymmetry of macroscopic and elementary calcium signals mediated by InsP3 in Xenopus oocytes.
Callamaras N
,
Sun XP
,
Ivorra I
,
Parker I
.
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1. The mechanisms underlying hemispheric asymmetry of the inositol 1, 4,5-trisphosphate (InsP3)-calcium signalling pathway in Xenopus oocytes were examined by fluorescence imaging of calcium signals and recording calcium-activated Cl- currents (ICl,Ca) evoked by intracellular calcium injections and photorelease of InsP3. 2. The maximal ICl,Ca evoked by strong photorelease of InsP3 was 8 times greater in the animal than the vegetal hemisphere, but the average threshold amounts of InsP3 required to evoke detectable currents were similar in each hemisphere. 3. Currents evoked by injections of calcium were about 2.5 times greater near the animal pole than near the vegetal pole, whereas fluorescence signals evoked by injections were similar in each hemisphere. 4. Calcium waves were evoked by photolysis flashes of similar strengths in both hemispheres of albino oocytes, but peak calcium levels evoked by supramaximal stimuli were 70 % greater in the animal hemisphere. 5. Elementary calcium release events (puffs) in the animal hemisphere had amplitudes about double that in the vegetal hemisphere, and more often involved coupled release from adjacent sites. Calcium release sites were more closely packed in the animal hemisphere, with a mean spacing of about 1.5 micro m compared with 2.25 micro m in the vegetal hemisphere. 6. The larger amplitude of currents mediated by InsP3 in the animal hemisphere, therefore, involves an increased flux of calcium at individual release units, a more dense packing of release units and a higher density of Cl- channels.
Berridge,
Neural and developmental actions of lithium: a unifying hypothesis.
1989, Pubmed
Berridge,
Neural and developmental actions of lithium: a unifying hypothesis.
1989,
Pubmed
Berridge,
Inositol trisphosphate and calcium signalling.
1993,
Pubmed
Berridge,
Elementary and global aspects of calcium signalling.
1997,
Pubmed
Berridge,
Inositol trisphosphate-induced membrane potential oscillations in Xenopus oocytes.
1988,
Pubmed
,
Xenbase
Callamaras,
Activation and co-ordination of InsP3-mediated elementary Ca2+ events during global Ca2+ signals in Xenopus oocytes.
1998,
Pubmed
,
Xenbase
Callamaras,
Inositol 1,4,5-trisphosphate receptors in Xenopus laevis oocytes: localization and modulation by Ca2+.
1994,
Pubmed
,
Xenbase
Callamaras,
Caged inositol 1,4,5-trisphosphate for studying release of Ca2+ from intracellular stores.
1998,
Pubmed
,
Xenbase
Dascal,
The use of Xenopus oocytes for the study of ion channels.
1987,
Pubmed
,
Xenbase
Gomez-Hernandez,
Calcium dependence and distribution of calcium-activated chloride channels in Xenopus oocytes.
1997,
Pubmed
,
Xenbase
Hartzell,
Activation of different Cl currents in Xenopus oocytes by Ca liberated from stores and by capacitative Ca influx.
1996,
Pubmed
,
Xenbase
Kume,
The Xenopus IP3 receptor: structure, function, and localization in oocytes and eggs.
1993,
Pubmed
,
Xenbase
Kusano,
Cholinergic and catecholaminergic receptors in the Xenopus oocyte membrane.
1982,
Pubmed
,
Xenbase
Lechleiter,
Molecular mechanisms of intracellular calcium excitability in X. laevis oocytes.
1992,
Pubmed
,
Xenbase
Lipp,
A hierarchical concept of cellular and subcellular Ca(2+)-signalling.
1996,
Pubmed
Lupu-Meiri,
Hemispheric asymmetry of rapid chloride responses to inositol trisphosphate and calcium in Xenopus oocytes.
1988,
Pubmed
,
Xenbase
Machaca,
Asymmetrical distribution of Ca-activated Cl channels in Xenopus oocytes.
1998,
Pubmed
,
Xenbase
Miledi,
Latencies of membrane currents evoked in Xenopus oocytes by receptor activation, inositol trisphosphate and calcium.
1989,
Pubmed
,
Xenbase
Miledi,
Chloride current induced by injection of calcium into Xenopus oocytes.
1984,
Pubmed
,
Xenbase
Neely,
Ca(2+)-dependent inactivation of a cloned cardiac Ca2+ channel alpha 1 subunit (alpha 1C) expressed in Xenopus oocytes.
1994,
Pubmed
,
Xenbase
Parker,
Relation between intracellular Ca2+ signals and Ca(2+)-activated Cl- current in Xenopus oocytes.
1994,
Pubmed
,
Xenbase
Parker,
A high-resolution, confocal laser-scanning microscope and flash photolysis system for physiological studies.
1997,
Pubmed
,
Xenbase
Parker,
Regenerative release of calcium from functionally discrete subcellular stores by inositol trisphosphate.
1991,
Pubmed
,
Xenbase
Parker,
Elementary events of InsP3-induced Ca2+ liberation in Xenopus oocytes: hot spots, puffs and blips.
1996,
Pubmed
,
Xenbase
Parker,
Fast kinetics of calcium liberation induced in Xenopus oocytes by photoreleased inositol trisphosphate.
1996,
Pubmed
,
Xenbase
Parys,
Isolation, characterization, and localization of the inositol 1,4,5-trisphosphate receptor protein in Xenopus laevis oocytes.
1992,
Pubmed
,
Xenbase
Peter,
The polarized distribution of poly(A+)-mRNA-induced functional ion channels in the Xenopus oocyte plasma membrane is prevented by anticytoskeletal drugs.
1991,
Pubmed
,
Xenbase
Rizzuto,
Microdomains with high Ca2+ close to IP3-sensitive channels that are sensed by neighboring mitochondria.
1993,
Pubmed
Stern,
Buffering of calcium in the vicinity of a channel pore.
1992,
Pubmed
Tigyi,
A serum factor that activates the phosphatidylinositol phosphate signaling system in Xenopus oocytes.
1990,
Pubmed
,
Xenbase
Yao,
Quantal puffs of intracellular Ca2+ evoked by inositol trisphosphate in Xenopus oocytes.
1995,
Pubmed
,
Xenbase
