1,720,965 research outputs found
Neuroexcitatory properties of kainic acid. II) Neuronal damages following intracerebral microinjections in behavioural rats.
No full textThe induction of cyclic nucleotide phosphodiesterase 4 gene (PDE4D) impairs memory in a water maze task
No full textIn this study, the effects on memory of intraperitoneal post-training administration of cyclic nucleotide phosphodiesterase (PDE)
inhibitors, DC-TA 46 and rolipram, were tested using a visible/hidden-platform water maze task. The effects of these compounds on cyclic
nucleotide levels in the hippocampal formation (HF) and striatum (CP) were also assessed, by enzymatic immunoassay (EIA). The results
obtained from rats trained in the visible-platform task were not significantly different from controls. On the contrary, the animals trained in
the hidden-platform water maze task showed a memory impairment, when injected with DC-TA 46 at maximal dose of 20 mg/kg and with
rolipram at 3 and 30 mg/kg doses. The effects of these drugs on cyclic nucleotide levels in HF and CP were observed at 30 min and at 24 h
after drug administration. Thirty minutes after drug injection, we observed an increase of cAMP level, both in HF and in CP. Twenty-four
hours after the retention test, we observed that in CP the cAMP intracellular level remained high, while in the HF at effective doses both
inhibitors induced cAMP PDE activity, determining a decrease of cyclic nucleotide. Semi-quantitative RT–PCR analysis, together with
Western blot immunodetection, showed a mRNA and protein induction of PDE4D PDE isoforms, that may account for the increase of PDE
activity observed. Our data suggest that, despite cyclic nucleotide increase at 30 min, the fundamental event causing memory impairment,
came from the subsequent long time decrease of cAMP levels, due to the post-translational PDE4D induction
The reciprocal influence between the nucleus tegmenti pedunculopontinus and the substantia nigra in the rat
No full textThe organization of nucleus tegmenti pedunculopontinus projections to basal ganglia and thalamus: a retrograde transport study
No full textAn EM and Golgi study of the connection between the nucleus tegmenti pedunculopontinus and the pars compacta of the substantia nigra in the rat
No full textElectrophysiological evidence for an inhibitory accumbens-entopeduncular pathway in the rat
No full textNeuroexcitatory properties of kainic acid. I) Electroencephalographic changes following intracerebral microinjections in behavioural rats. Preliminary note.
No full textA microiontophoretic study on the nature of the putative synaptic neurotransmitter involved in the pedunculopontine-substantia nigra pars compacta excitatory pathway
No full textResponsiveness of nigral neurons to the stimulation of striatal dopaminergic receptors in the rat
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