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1. The depressant actions of Mg2+ and a range of other divalent ions on synaptic excitation and on responses produced by excitatory amino acids and other putative transmitters have been investigated in hemisected isolated spinal cords of frogs and neonatal rats. Some comparative studies were also made using the rat isolated superior cervical ganglion. 2. At(More)
Trisomy 21 (Down syndrome) results in abnormalities in electrical membrane properties of cultured human fetal dorsal root ganglion (DRG) neurons. Action potentials have faster rates of depolarization and repolarization, with decreased spike duration, compared to diploid neurons. In order to analyze the faster depolarization rate observed in trisomic(More)
The trisomy-16 mouse is considered to be a model of human trisomy-21 (Down syndrome). We have examined the electrical membrane properties of cultured dorsal root ganglion (DRG) neurons from normal and trisomy-16 fetuses. Trisomy-16 neurons had significantly accelerated rates of action potential depolarization and repolarization compared to diploid neurons,(More)
The effects of baclofen, an antispastic drug, on excitatory transmission were tested by bath application to the hippocampal slice preparation. (+/-)-Baclofen (20 microM) strongly depressed extracellularly recorded synaptic responses to stimulation of projections that originate from CA3 hippocampal pyramidal cells. Responses to stimulation of four other(More)
The ability of adenosine and structurally-related compounds to inhibit epileptiform activity induced by bicuculline in the CA3 region of the hippocampal slice of the rat was examined. Bath application of all purinoceptor agonists tested reduced the frequency of generation of burst potentials. Analysis of dose-response curves yielded the following IC50(More)
Algogens such as capsaicin, bradykinin, acetylcholine, 5-hydroxytryptamine and potassium ions applied to exposed tail skin of the rat isolated spinal cord-tail preparation evoke a ventral root response consisting of depolarization and spiking activity. L-glutamate and kainate also evoke similar reflexes. All these compounds evoke depolarization of afferent(More)
1 The effects of baclofen were tested on epileptiform discharge in the rat hippocampal slice. Slices were superfused with bicuculline methiodide (100 microM) and maximal periods of afterdischarge were evoked by stimulating the Schaffer collateral-commissural pathway in area CA1, mossy fibres in area CA3 or perforant path fibres in the fascia dentata or by(More)
Our recent whole cell patch-pipette studies have shown that human trisomy 21 (Down syndrome) cultured fetal dorsal root ganglion (DRG) neurons have accelerated rates of action potential depolarization and repolarization, with reduced spike duration, compared to control neurons. Similar observations were made using DRG neurons from the trisomy 16 mouse, an(More)
The pro-convulsant actions of theophylline and caffeine have been investigated using the hippocampal slice preparation and rats administered kainic acid or Metrazol. Both theophylline and caffeine induced the generation of epileptiform activity in the CA3 region of the hippocampal slice with convulsive dose50 (CD50) values of 3 microM respectively. Kainic(More)