Spatial distribution of fluorescence intensity within large droplets and its dependence on dye concentration.

The dependence of fluorescence intensity distributions within droplets on added dye concentration has been calculated by extension of the geometrical-optics approximation and verified by experimental observations. With rising dye concentration, surface plots of the equatorial fluorescence pattern show decreasing relevance of intensity enhancement at focusing points of internal light rays and increasing effects of linear absorption on the characteristic features of the distribution. For comparison with experimentally obtained images of the fluorescence intensity distribution within droplets, a method for calculating volume-integrated intensity distributions was developed in which image distortion at the fluid-air interface is included.

Lead reduces depolarization-induced calcium entry in cultured DRG neurons without crossing the cell membrane: fura-2 measurements.

1. Cultured dorsal root ganglion of rat pups were depolarized by exposure to 50 mM K+ and the rise of [Ca2+]i was measured using fura-2 as an indicator. 2.

Inhibitory mechanisms in epileptiform activity induced by low magnesium.

In rat hippocampal slices epileptiform activity was induced by superfusion with Mg(2+)-free artificial cerebrospinal fluid (ACSF). Paroxysmal depolarization shifts (PDS) were evoked by electrical stimulation of Schaffer collaterals. To investigate the afterpotentials that follow PDS, intracellular recordings were made from CA1 pyramidal cells.

Inhibitory mechanisms terminating paroxysmal depolarization shifts in hippocampal neurons of rats.

The mechanisms responsible for the termination of paroxysmal depolarization shifts (PDS) were studied with intracellular recordings on CA1 neurons of rat hippocampal slices. Epileptiform activity was induced by application of penicillin, bicuculline or Mg-free artificial cerebrospinal fluid (ACSF). PDS in penicillin-containing and Mg-free ACSF were markedly prolonged when GABAA-dependent IPSPs were blocked by bicuculline.