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Copyright © 1998 by Institute of Pharmacology Polish Academy of Sciences |
Pol. J. Pharmacol., 1998, 50, 39-45 ISSN 1230-6002 |
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Effects of the dihydropyridine calcium antagonist nimodipine on the firing rate of cat visual neurons
after systemic administration. H. J. KOCH. Pol. J. Pharmacol., 1998, 50, 39-45. Nimodipine, a cerebrovasotropic dihydropyridine calcium antagonist, has gained increasing interest in geriatric research during last years and is discussed with regard to its possible involvement in restoration and preservation of brain plasticity. Single unit responses were recorded in the visual cortex of anaesthetized adult cats. Receptive fields (rf) were stimulated with light bars moving forward and backward or flashed on/off. Neuronal responses were analysed by means of peri-stimulus-time-histograms (PSTH). While stimulated with the flashing light the majority of neurons showed the same pattern of responses to nimodipine: PSTH peak was reduced 5 min after the injection and rose again in 30 min. The influence of nimodipine was more variable after stimulation with moving bars. 60% of neurons decreased and 40% increased their responses after the injection. In conclusion, the findings show that nimodipine has specific neurotropic effects which are independent of its vasodilatatory properties. Key words: calcium channel blocker, visual cortex, peri-stimulus-time-histogram, neurotropic effect |
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