Navegando por Palavras-chave "substantia nigra"
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- ItemSomente MetadadadosDietary riboflavin restriction and chronic hemin administration does not alter brain function in rats: The importance of vitamin homeostasis in the brain(New Century Health Publishers, Llc, 2007-11-01) DalPai, Janise [UNIFESP]; Borges, Andrea Aurélio [UNIFESP]; Grassl, Christian [UNIFESP]; Favero Filho, Luiz Antonio [UNIFESP]; Xavier, Gilberto Fernando [UNIFESP]; Junqueira, Virginia Berlanga Campos [UNIFESP]; Lopes, Antonio Carlos [UNIFESP]; Coimbra, Cicero Galli [UNIFESP]; Sinigaglia-Coimbra, Rita [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Vitamin B2 deficiency associated with normal dietary intake has been reported inpatients with Parkinson disease (PD), suggesting impaired absorption of this micronutrient. Elevated red meat consumption was thought to contribute as a triggering factor, as the catabolism of hemin (a neurotoxic substance) requires vitamin B2 (Coimbra &Junqueira, 2003). This study tested this hypothesis by verifying the effects of dietary riboflavin restriction associated with hemin administration on rat brain. After 8 months of riboflavin restriction, riboflavin deficiency with or without oral administration of hemin (assessed by erythrocyte glutathion ereductase activity) did not impair motor function or spatial learning; neither altered the volume of substantia nigra or brain concentrations of total glutathione. Partial dietary restriction of riboflavin may failed to induce oxidative stress in the rat brain and dopaminergic degeneration in the rat substantia nigra as suggested to occur in humans by Coimbra & Junqueita, (2003), possibly due to an intact mechanism of nutritional privilege that preserves riboflavin content in the normal rat brain during deficiency states. Contrastingly, polymorphic enzymes or receptors involved in the human cellular uptake of ribofiavin may conceivably impair the transport of this micronutrient not only through the intestinal wall and renal tubules, but also in the brain of PD patients, there by annulling the nutritional privilege of the nervous system.
- ItemSomente MetadadadosEffects of Allogeneic Bone Marrow Derived Mesenchymal Stromal Cell Therapy on Voiding Function in a Rat Model of Parkinson Disease(Elsevier B.V., 2014-03-01) Campeau, Lysanne; Soler, Roberto [UNIFESP]; Sittadjody, Sivanandane; Pareta, Rajesh; Nomiya, Masanori; Zarifpour, Mona; Opara, Emmanuel C.; Yoo, James J.; Andersson, Karl-Erik; Wake Forest Univ; NYU; Universidade Federal de São Paulo (UNIFESP); Fukushima Med UnivPurpose: Cellular therapy induced transient urodynamic improvement in a rat model of Parkinson disease in which bladder dysfunction was noted after unilateral injection of 6-hydroxydopamine into the medial forebrain bundle. We sought to prolong the effect by injecting allogeneic rat bone marrow mesenchymal stromal cells before and after microencapsulation into the substantia nigra pars compacta.Materials and Methods: Female rats underwent unilateral stereotactic injection of 6-hydroxydopamine in the medial forebrain bundle. Injection was performed in the ipsilateral substantia nigra pars compacta using vehicle alone or vehicle with nonmicroencapsulated or microencapsulated rat bone marrow derived mesenchymal stromal cells. Rats were evaluated by cystometry 7, 14, 28 and 42 days after treatment. Brains were extracted for immunostaining.Results: At 42 days the nonmicroencapsulated group had lower threshold and intermicturition pressure, spontaneous activity and AUC than vehicle treated animals. Rats that received microencapsulated cells had lower threshold pressure at 28 days and lower spontaneous activity at 42 days than vehicle treated rats. Microencapsulated and nonmicroencapsulated rat bone marrow derived mesenchymal stromal cells were noted in the substantia nigra pars compacta up to 42 days after transplantation. At 42 days tyrosine hydroxylase positive neurons were more numerous in the substantia nigra pars compacta of the nonmicroencapsulated group, followed by the microencapsulated and vehicle treated groups.Conclusions: Urodynamic effects of the 6-hydroxydopamine lesion persisted up to 42 days after vehicle injection. Transplantation of nonmicroencapsulated rat bone marrow derived mesenchymal stromal cells improved urodynamic pressure by 42 days after treatment more markedly than microencapsulated cells. This was associated with more tyrosine hydroxylase positive neurons in the treated substantia nigra pars compacta of the nonmicroencapsulated group, suggesting that functional improvement requires a juxtacrine effect.
- ItemSomente MetadadadosEffects of microinjections of neurotoxin AvTx8, isolated from the social wasp Agelaia vicina (Hymenoptera, Vespidae) venom, on GABAergic nigrotectal pathways(Elsevier B.V., 2005-01-07) Oliveira, L. de; Cunha, AOS; Mortari, M. R.; Pizzo, A. B.; Miranda, A.; Coimbra, N. C.; Santos, W. F. dos; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)Several investigations have provided information that defensive behaviors evoked by stimulation of deep layers of the superior colliculus (dISC) are subjected to inhibitory nigral modulation. This inhibition is made mainly through GABAergic neurons from substantia, nigra, pars reticulata (SNpr), that sends outputs toward neural networks of the deep layers of the superior colliculus and dorsal periaqueductal gray matter involved with the organization of fear-like responses. in this work, we compared the effects of two GABAergic agonists, muscimol and baclofen, with the effect of neurotoxin AvTx8 (1567 Da), isolated from the venom of the social wasp Agelaia vicina, microinjected into SNpr of Rattus norvegicus (Wistar rats) prior to dISC saline or bicuculline microinjections, considering that wasp venom has some influence on the uptake of GABA and/or glutamate neurotransmitters. GABA(A) receptor blockade in the dISC evoked a vigorous escape behavior, expressed by rapid running, jumps and turns, as compared to control. These defensive reactions were maximized after the intranigral GABA(A) agonism with muscimol, but not after in situ GABA(B) agonism. Nigral microinjection of AvTx8 induced similar effects to those of baclofen, decreasing the intensity of behavioral defensive reactions caused by GABA(A) receptor blockade in the dorsal mesencephalon. These findings suggest that AvTx8 has some effects on GABAergic neurotransmission, increasing the activity of the inhibitory nigrocollicular pathways, causing an anti-panic (antiaversive) effect. Therefore, our work suggests AvTx8 as a novel pharmacological tool to study differences between the two types of GABAergic receptors and excitatory amino acid-mediated mechanisms in the brain and brainstem networks. (C) 2004 Elsevier B.V. All rights reserved.