Subject(s)
Central Nervous System/physiology , Dopamine/physiology , Parasympathetic Nervous System/physiology , Substantia Nigra/physiology , Synapses/physiology , Animals , Apomorphine/pharmacology , Behavior, Animal/drug effects , Carbachol/pharmacology , Corpus Striatum/metabolism , Dopamine/metabolism , Electroencephalography , Homovanillic Acid/metabolism , Male , RabbitsABSTRACT
Unilateral injections of carbachol (CCh, 2 mul) to lateral parts of substantia nigra (SNlat) of the rabbit increased the alert index (participation of alert pattern in EEG), produced epileptoidal EEG discharges, sniffing, ipsi- and contralateral rotations, and abnormal movements of fore limbs, which may be regarded as an equivalent of localized seizures. Ipsilateral rotations appeared together with epileptoidal discharges confined to SNlat, while contralateral -- with discharges in ventrolateral thalamic nucleus (VLTh). The EEG discharges appeared firstly and had the longest duration in VLTh. Injection of CCh to medial substantia nigra (SNmed) did not produce contralateral turnings and rotations, and epileptoidal EEG discharges appeared primarily in SNmed. In rabbits with previously lesioned nigro-neostriatal pathway (NSP) at the level of Forel's fields, the EEG discharges produced by CCh injected into SNlat appeared firstly and were most prolonged in SNlat, while they appeared much later in caudate nucleus (NC), cerebral cortex, and VLTh. The contralateral rotations were inhibited, and ipsilateral ones -- potentiated in the lesioned rabbits.
Subject(s)
Caudate Nucleus/physiology , Substantia Nigra/physiology , Thalamus/physiology , Animals , Anura , Atropine/pharmacology , Brain Chemistry , Carbachol/pharmacology , Catecholamines/analysis , Electrodes, Implanted , Electroencephalography , Electromyography , Gallamine Triethiodide/pharmacology , Humans , In Vitro Techniques , Indoles/analysis , Injections , Male , Neural Conduction/drug effects , Neural Pathways/physiology , Rabbits , Rana temporaria , Stereotyped Behavior/drug effectsABSTRACT
Bioelectrical activity of chronically implanted rabbits was studied after different doses of ouabain (0.25-1.5 microg) administered topically on the extrapyramidal cortex. The results indicate that the EEG effect of ouabain (relax pattern, epileptiform activity or spreading depression) depends on the dose employed. It is interesting that epileptiform activity appeared in the ipsilateral caudate nucleus during phenomena similar to the 'spreading depression' in the ipsilateral extrapyramidal cortex, i.e. in the site of ouabain administration.