Local Ca2+ transients (Ca2+ sparks) originate at transverse tubules in rat heart cells.

1. The origins of local [Ca2+]i transients (Ca2+ sparks) were studied using dual-channel confocal laser scanning microscopy. Line scan images showing [Ca2+]i (as fluo-3 fluorescence) and the transverse tubule membranes (as Di-8 fluorescence) were obtained simultaneously in single rat cardiac ventricular cells.

Local calcium transients triggered by single L-type calcium channel currents in cardiac cells.

Excitation-contraction coupling was studied in mammalian cardiac cells in which the opening probability of L-type calcium (Ca2+) channels was reduced. Confocal microscopy during voltage-clamp depolarization revealed distinct local transients in the concentration of intracellular calcium ions ([Ca2+]i). When voltage was varied, the latency to occurrence and the relative probability of occurrence of local [Ca2+]i transients varied as predicted if Ca2+ release from the sarcoplasmic reticulum (SR) was linked tightly to Ca2+ flux through L-type Ca2+ channels but not to that through the Na-Ca exchanger or to average [Ca2+]i.

Simultaneous measurements of Ca2+ and nitric oxide in bradykinin-stimulated vascular endothelial cells.

The production of endothelium-derived relaxing factor (EDRF), known to be nitric oxide (NO), is triggered by a rise in the cytoplasmic calcium concentration ([Ca2+]i) subsequent to receptor binding of vasoactive agonists. In vascular endothelial cells, NO is synthesized from L-arginine by the Ca2+/calmodulin-dependent NO synthase. In this study, we report the first simultaneous measurements of [Ca2+]i and [NO] at the level of single endothelial cells.

Sport-related eye trauma: a survey of the presentation of eye injuries to a casualty clinic and the use of protective eye-wear.

The study investigated the workload offered by sport-related trauma to a busy casualty clinic and was carried out in two parts. The first part concerned compiling information about sport-related injuries presenting in 1 year to the outpatient eye clinic at Bradford Royal Infirmary. The second part attempted to investigate the awareness and the use of eye-protectors for squash by the student community of Bradford University, using a questionnaire.

Calcium signalling in cardiac muscle cells.

In heart cells, several distinct kinds of transient spatial patterns of cytoplasmic calcium ion concentration ([Ca2+]i) can be observed: (1) [Ca2+]i waves, in which regions of spontaneously increased [Ca2+]i propagate at high velocity (100 microns/s) through the cell; (2) Ca2+ 'sparks', which are spontaneous, non-propagating changes in [Ca2+]i that are localized in small (approximately 2 microns) subcellular regions; and (3) evoked [Ca2+]i transients that are elicited by electrical depolarization, in association with normal excitation-contraction (E-C) coupling. In confocal [Ca2+]i images, evoked [Ca2+]i transients appear to be nearly spatially uniform throughout the cell, except during their rising phase or during small depolarizations. In contrast to [Ca2+]i waves and spontaneous Ca2+ sparks, evoked [Ca2+]i transients are triggered by L-type Ca2+ channel current and they are 'controlled', in the sense that stopping the L-type Ca2+ current stops them.

Local, stochastic release of Ca2+ in voltage-clamped rat heart cells: visualization with confocal microscopy.

1. Confocal microscopy and the fluorescent Ca2+ indicator fluo-3 (K+ salt) were used to measure cytosolic free calcium ion concentration ([Ca2+]) during excitation-contraction (E-C) coupling in single, voltage-clamped, rat cardiac ventricular cells. 2.

Kainic acid and 1'-hydroxykainic acid from Palmariales.

The distribution of kainic acid among various red algae was investigated. Analysis of free amino acids from different populations of Palmaria palmata showed that some were unable to accumulate kainic acid to detectable concentrations, whereas in two dwarf mutants it was a major component of the free amino acid composition. The amino acid profiles were also examined for unknown amino acids in the search for possible intermediates in kainic acid biosynthesis.

Detection in Vivo of Very Rapid Red Light-Induced Calcium-Sensitive Protein Phosphorylation in Etiolated Wheat (Triticum aestivum) Leaf Protoplasts.

Etiolated wheat (Triticum aestivum cv Mercia) leaf protoplasts respond to brief red-light irradiation by increasing in volume over a 10-min incubation period (M.E. Bossen, H.