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The substantia nigra (SN) is a midbrain center composed of dopaminergic (DA-) and gamma aminobutyric acid (GABA)ergic (GABA-) neurons. In this study, we investigated the topographical relationship between both cell populations and their chemical profile by using single and double immunostaining for tyrosine hydroxylase (TH), glutamic acid decarboxylase(More)
Movement asymmetry in humans and animals is often considered as being induced by the brain lateralization of the motor system. In the present work, the hemispheric asymmetry for motor planning as a cause of behavioral lateralization was examined. This study was carried out on normal volunteers and patients suffering unilateral brain damage caused by a(More)
Astroglial participation in the regional differences of vulnerability to alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-induced neurodegeneration was investigated in the rat hippocampus and medial septum using L-alpha-aminoadipate (alpha-AA) as a specific astroglial toxin. alpha-AA was microinjected in the hippocampus and the medial septum(More)
Although dopamine has been considered as the only neurotransmitter in the nigrostriatal pathway, studies carried out in the last two decades have suggested the existence of a nondopaminergic nigrostriatal projection, and more recently, gamma-aminobutyric acid (GABA) has been identified as its neurotransmitter. In this study, we used the combination of(More)
The dopamine transporter (DAT) is a membrane glycoprotein responsible for dopamine (DA) uptake, which has been involved in the degeneration of DA cells in Parkinson's disease (PD). Given that DAT activity depends on its glycosylation status and membrane expression, and that not all midbrain DA cells show the same susceptibility to degeneration in PD, we(More)
Activation of excitatory amino acid (EAA) receptors can induce neurodegeneration by two major mechanisms of excitotoxicity, one related to the influx of Na(+), Cl(-) and water, and the other to the increase in intracellular calcium concentration ([Ca(2+)](i)). Thus, acute microinjection of EAAs in several areas of the central nervous system (CNS) has been(More)
The authors studied the possible involvement of the cerebellum in nonexecutive motor functions needed for a normal performance of complex motor patterns by analyzing (using chronometric evaluation) finger movement sequences and their respective motor imagery (a mental simulation of motor patterns). Patients suffering from a cerebellar stroke (n=11) were(More)
Previous studies have suggested the increase of extracellular glutamate (GLU) in the substantia nigra (SN) as a cause of dopamine-cell degeneration (excitotoxicity) in Parkinson's disease (PD). However, the mechanisms involved in this increase remain unknown. The present work studied osmoregulation as a cause of GLU release in the SN. Microdialysis was used(More)
The basal ganglia are part of a neuronal network organized in parallel circuits. The "motor circuit" is most relevant to the pathophysiology of movement. Abnormal increment or reduction in the inhibitory output activity of basal ganglia give rise, respectively, to poverty and slowness of movement (i.e., Parkinson's disease) or dyskinesias.
Although dopamine is the main neurotransmitter in the mesostriatal system, recent studies indicate the existence of two nigrostriatal GABAergic projections: one arising from neurons immunoreactive for GABA, glutamic acid decarboxylase (GAD67), and parvalbumin (PV) lying in the substantia nigra pars reticulata (nigrostriatal GABA cells) and the other arising(More)