Navegando por Palavras-chave "neurotransmitter"

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    Evidence for neuronal release of isotopically labelled glycine from the rat ventral medullary surface in vivo
    (Assoc Bras Divulg Cientifica, 1996-04-01) deOliveira, CVR; Assumpção, Jurandyr D'Avila [UNIFESP]; Confessor, Yara Queiroga [UNIFESP]; Guertzenstein, Pedro Gaspar [UNIFESP]; Cravo, Sergio Luiz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Spontaneous and stimulus-induced release of isotopically labelled glycine was studied in the superfused rat dorsal or ventral medullary surface in vivo. Superfusion of the ventral medullary surface of anesthetized (urethane, 1.2 g/kg, ip) male adult Wistar rats (250-350 g) with high K+ (40 mM) surrogate cerebrospinal fluid (CSF) produced an average increase of 45% over the spontaneous efflux of exogenously applied glycine (N = 5, P<0.01). In experiments in which the calcium of the CSF was replaced by an equimolar amount of magnesium, the increase in glycine efflux in response to high K+ was reduced to 15%, a value not statistically different from that observed in control experiments (N = 6). Veratridine stimulation evoked a large (80%) increase in glycine efflux (N = 5, P<0.001), which was inhibited by tetrodotoxin. High potassium or veratridine failed to modify spontaneous release of glycine on the dorsal medullary surface. Results obtained in control experiments showed that neither high K+ nor veratridine is effective in modifying spontaneous efflux of [H-3]-leucine or [H-3]-inulin on the ventral or dorsal medullary surface. These data support the hypothesis that glycine is a neurotransmitter on the ventral medullary surface and that it may be part of neural pathways involved in cardiorespiratory regulation present in this region.
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    New insights into purinergic receptor signaling in neuronal differentiation, neuroprotection, and brain disorders
    (Springer, 2007-09-01) Majumder, Paromita; Trujillo, Cleber Augusto; Lopes, Camila Galvão; Resende, Rodrigo Ribeiro; Gomes, Katia das Neves; Yuahasi, Katia Kioko [UNIFESP]; Britto, Luiz Roberto Giorgetti de; Ulrich, Henning; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    Ionotropic P2X and metabotropic P2Y purinergic receptors are expressed in the central nervous system and participate in the synaptic process particularly associated with acetylcholine, GABA, and glutamate neurotransmission. As a result of activation, the P2 receptors promote the elevation of free intracellular calcium concentration as the main signaling pathway. Purinergic signaling is present in early stages of embryogenesis and is involved in processes of cell proliferation, migration, and differentiation. the use of new techniques such as knockout animals, in vitro models of neuronal differentiation, antisense oligonucleotides to induce downregulation of purinergic receptor gene expression, and the development of selective inhibitors for purinergic receptor subtypes contribute to the comprehension of the role of purinergic signaling during neurogenesis. in this review, we shall discuss the participation of purinergic receptors in developmental processes and in brain physiology, including neuron-glia interactions and pathophysiology.