W. J. Wadman

Learn More
Spatially resolved measurements of intracellular free calcium and of the changes produced by excitatory amino acids were made in neurons isolated from adult mammalian brain. Extremely long-lasting (minutes) Ca2+ gradients were induced in the apical dendrites of hippocampal CA1 neurons after brief (1 to 3 seconds), local application of either glutamate or(More)
To explore non-synaptic mechanisms in paroxysmal discharges, we used a computer model of a simplified hippocampal pyramidal cell, surrounded by interstitial space and a “glial-endothelial” buffer system. Ion channels for Na+, K+, Ca2+ and Cl− , ion antiport 3Na/Ca, and “active” ion pumps were represented in the neuron membrane. The glia had “leak”(More)
1. Neurones were isolated from the hippocampus of adult guinea-pigs by enzymatic and mechanical treatment. The electrophysiological properties of these cells were examined immediately after dissociation by intracellular recordings using low-resistance electrodes (2-5 M omega). 2. Pyramidal-shaped cells were identified visually. Intracellular recordings(More)
In the present study we describe the excitatory effects of the bioactive peptide neurotensin on the electrical activity of dopamine neurons (simultaneously recorded) in the substantia nigra pars compacta and the ventral tegmental area. The neurotensin fragment (8-13) induced comparable increases in firing rate of the substantia nigra and ventral tegmental(More)
Extracellular potassium concentration, [K+]o, and intracellular calcium, [Ca2+]i, rise during neuron excitation, seizures and spreading depression. Astrocytes probably restrain the rise of K+ in a way that is only partly understood. To examine the effect of glial K+ uptake, we used a model neuron equipped with Na+, K+, Ca2+ and Cl− conductances, ion pumps(More)
Spatiotemporal changes of the intracellular calcium ion (Ca2+) were recorded by digital ratio imaging of fura-2 in pyramidal neurons acutely isolated from the adult guinea-pig hippocampus. Increases in calcium were evoked in tetrodotoxin (2 microM) containing saline either by stimulation with the excitatory amino acids, glutamate or N-methyl-D-aspartate, or(More)
Repetitive electrical stimulation and application of excitatory amino acids lead to decreases in extracellular Ca2+ concentration and to rises in extracellular K+ concentration [( Ca2+]o, [K+]o) with a typical laminar distribution in a given neo- or allocortical structure. These ionic changes result from transmembrane ion fluxes along their respective(More)
The classification of dopamine receptors proposed more than two decades ago remains valid today. Based on biochemical and pharmaceutical properties two main classes of dopamine receptors can be distinguished: D(1)-like (D(1), D(5)) and D(2)-like (D(2), D(3), and D(4)) dopamine receptors. Dopamine receptors belong to the class of G protein-coupled receptors(More)
 The degree to which osmotic stress changes the volume of mammalian central neurons has not previously been determined. We isolated CA1 pyramidal cells and measured cell volume in four different ways. Extracellular osmolarity (πo) was lowered by omitting varying amounts of NaCl and raised by adding mannitol; the extremes of πo tested ranged from 134 to 396(More)
The distribution of the olfactory afferents within the ventrolateral part of the entorhinal cortex (EC) was studied by means of field potentials evoked by stimulation of the olfactory bulb (OB) and the olfactory cortex (PPC). Depth profiles of the field potentials evoked by OB or PPC stimulation were studied using current source density analysis. After OB(More)