Navegando por Palavras-chave "Prepulse inhibition"
Agora exibindo 1 - 6 de 6
Resultados por página
Opções de Ordenação
- ItemSomente MetadadadosAtypical antipsychotic clozapine reversed deficit on prepulse inhibition of the acoustic startle reflex produced by microinjection of DOI into the inferior colliculus in rats(Elsevier Science Bv, 2017) Oliveira, Rodolpho Pereira de [UNIFESP]; Nagaishi, Karen Yuriko [UNIFESP]; Silva, Regina Cláudia Barbosa da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Dysfunctions of the serotonergic system have been suggested to be important in the neurobiology of schizophrenia. Patients with schizophrenia exhibit deficits in an operational measure of sensorimotor gating: prepulse inhibition (PPI) of startle. PPI is the normal reduction in the startle response caused by a low intensity non-startling stimulus (prepulse) which is presented shortly before the startle stimulus (pulse). Tile hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI), a 5-hydroxytryptamine(HT)2 receptor agonist disrupted PPI in rats. The inferior colliculus (IC) is a critical nucleus of the auditory pathway mediating acoustic PPI. The activation of the IC by the acoustic prepulse reduces startle magnitude. The present study investigated the role of serotonergic transmission in the IC on the expression of acoustic PPI. For that we investigated whether 5-HT2A receptor activation or blockade would affect this response. Unilateral microinjection of DOI (10 mu g,/0.3 mu L ) into the IC disrupted PPI, while microinjection of the 5-HT2A receptor antagonist ritanserin (4 p,mu g/0.3 mu l), into this structure did not alter PPI. We also examined the ability of the atypical antipsychotic clozapine (5.0 mg/kg I.P.) to reverse the disruption of PPI produced by unilateral microinjections of DOI into the IC of rats. Pretreatment with clozapine blocked DOI-induced disruption of PPI. Altogether, these results suggest that serotonin-mediated mechanisms of the IC are involved in the expression of PPI in rodents and that this response is sensitive to atypical antipsychotic clozapine.
- ItemSomente MetadadadosAtypical antipsychotic olanzapine reversed deficit on prepulse inhibition of the acoustic startle reflex produced by microinjection of dizocilpine (MK-801) into the inferior colliculus in rats(Elsevier B.V., 2013-11-15) Zangrando, Julia [UNIFESP]; Carvalheira, Renata [UNIFESP]; Labbate, Giovanna Puosso [UNIFESP]; Medeiros, Priscila [UNIFESP]; Longo, Beatriz Monteiro [UNIFESP]; Melo-Thomas, Liana [UNIFESP]; Silva, Regina Cláudia Barbosa da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Patients with schizophrenia exhibit deficits in an operational measure of sensorimotor gating: prepulse inhibition (PPI) of startle. PPI is the normal reduction in the startle response caused by a low intensity non-startling stimulus (prepulse) which is presented shortly before the startle stimulus (pulse). MK-801 is an NMDA receptor-antagonist known to produce hyperactivity, deficits in prepulse inhibition and social withdrawal, behaviors which correlate well with some of the positive, cognitive and negative symptoms of schizophrenia. the inferior colliculus (IC) is a critical part of the auditory pathway mediating acoustic PPI. the activation of the IC by the acoustic prepulse reduces startle magnitude. Thus, the purpose of the present study was to elucidate the role of glutamatergic transmission in the IC on the expression of acoustic PPI. for that we investigated whether NMDA receptor stimulation or blockade would affect this response. Unilateral microinjections of NMDA (30 nmol/0.5 mu L) into the IC did not alter PPI while microinjections of MK-801 (30 nmol/0.5 mu L) into this structure disrupted PPI. We also examined the ability of the atypical antipsychotic olanzapine (5.0 mg/kg; i.p.) to reverse the disruption of pre-pulse inhibition produced by unilateral microinjections of MK-801 into the IC of rats. Pretreatment with olanzapine blocked MK-801-induced disruption of PPI. Altogether, these results suggest that glutamate-mediated mechanisms of the IC are involved in the expression of PPI in rodents and that this response is sensitive to atypical antipsychotic olanzapine. (C) 2013 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosEffect of severe neonatal seizures on prepulse inhibition and hippocampal volume of rats tested in early adulthood(Elsevier B.V., 2014-05-07) Labbate, Giovanna Puosso [UNIFESP]; Silva, Alexandre Valotta da [UNIFESP]; Silva, Regina Cláudia Barbosa da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Several lines of evidence indicate that the risk of developing schizophrenia is significantly enhanced following postnatal exposure to environmental insults occurring during the critical periods of early central nervous system development. the hippocampus is a brain structure that has been associated with the neuropathology of schizophrenia. Neonatal epileptic seizures in rat pups can affect the construction of hippocampal networks. Patients with schizophrenia exhibit deficits in an operational measure of sensorimotor gating: prepulse inhibition (PPI) of startle. PPI is the normal reduction in the startle response caused by a low intensity non-startling stimulus (prepulse) which is presented shortly before the startle stimulus (pulse). the aim of the present study was to investigate if prolonged epileptic seizures, occurring during postnatal brain development, alter prepulse inhibition (PPI) response of acoustic startle reflex and hippocampal volume of rats tested later in life (post-pubertal phase). Pilocarpine-induced status epilepticus (SE) was induced in postnatal days (PNDs) 7-9 in rat pups. On PND56, the animals were tested in the acoustic startle/PPI paradigm. Hippocampal volume was measured in histological brain slices using the Cavalieri's principle. Dorsal and ventral hippocampi were measured bilaterally. Our results demonstrate that animals subjected to SE presented deficits in PPI when tested in adulthood. Dorsal hippocampal volume was reduced in rats that experienced severe neonatal seizures. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
- ItemAcesso aberto (Open Access)Effects of microinjections of apomorphine and haloperidol into the inferior colliculus on prepulse inhibition of the acoustic startle reflex in rat(Elsevier B.V., 2012-02-10) Satake, Susan [UNIFESP]; Yamada, Karen Yukie [UNIFESP]; Melo, Liana Lins [UNIFESP]; Silva, Regina Cláudia Barbosa da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Prepulse inhibition (PPI) is the reduction in the startle response caused by a low intensity non-startling stimulus (prepulse) which is presented shortly before the startle stimulus and is an operational measure of sensorimotor gating. PPI is impaired in schizophrenia patients and in rats with central dopamine (DA) activation. the inferior colliculus (IC) is a critical part of the auditory pathway mediating acoustic PPI. the activation of the IC by the acoustic prepulse reduces startle magnitude. the aim of this study was to elucidate the role of DA transmission of the IC on the development of acoustic PPI. Bilateral microinjections of apomorphine (9.0 mu g/0.5 mu L) an agonist of D-2 receptors, into the IC disrupted PPI while microinjections of haloperidol (0.5 mu g/0.5 mu L), an antagonist of D-2 receptors, into this structure did not alter PPI. These results suggest that dopamine-mediated mechanisms of the IC are involved in the expression of PPI in rodents. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
- ItemAcesso aberto (Open Access)Hippocampal ether-a-go-go1 potassium channels blockade: Effects in the startle reflex and prepulse inhibition(Elsevier B.V., 2014-01-24) Issy, Ana Carolina; Fonseca, José Roberto Falco [UNIFESP]; Pardo, Luis Angel; Stuehmer, Walter; Del Bel, Eliane Aparecida; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Max Planck Inst Expt MedRecently, our group described the ether-a-go-go1(Eag1) voltage-gated potassium (K+) channel (Kv10.1) expression in the dopaminergic cells indicating that these channels are part of the diversified group of ion channels related to dopaminergic neurons function. the increase of dopamine neurotransmission induces a reduction in the prepulse inhibition (PPI) of the acoustic startle reflex in rodents, which is a reliable index of sensorimotor gating deficits. the PPI response has been reported to be abnormally reduced in schizophrenia patients. the role of Eag1 K+ channels in the PPI reaction had not been revealed until now, albeit the singular distribution of Eag1 in the dentate gyrus of the hippocampus and the hippocampal regulation of the startle reflex and PPI. the aim of this work was to investigate if Eag1 blockade on hippocampus modifies the PPI-disruptive effects of apomorphine in Wistar rats. Bilateral injection of anti-Eag1 single-chain antibody into the dentate gyrus of hippocampus did not modify apomorphine-disruptive effects in the PPI response. However, Eag1 antibody completely restored the startle amplitude decrease revealed after dentate gyrus surgery. These potentially biological important phenomenon merits further investigation regarding the role of Eag1 K+ channels, mainly, on startle reflex modulation, since the physiological role of these channels remain obscure. (C) 2013 Elsevier Ireland Ltd. All rights reserved.
- ItemAcesso aberto (Open Access)Participação da neurotransmissão endocanabinoide do colículo inferior, via modulação dos receptores CB1, na resposta de inibição por pré-pulso do reflexo de sobressalto acústico em ratos Wistar(Universidade Federal de São Paulo, 2023-02-27) Correia, Vanessa Zavarize Costa [UNIFESP]; Silva, Regina Cláudia Barbosa da [UNIFESP]; http://lattes.cnpq.br/7507421915981968; http://lattes.cnpq.br/2220442257175838; Universidade Federal de São Paulo (UNIFESP)A esquizofrenia é um transtorno psiquiátrico devastador que afeta aproximadamente 1% da população em geral ao longo da vida. Entre as várias hipóteses neuroquímicas consideradas para explicar a etiologia da esquizofrenia, destaca-se um possível envolvimento do sistema endocanabinóide (SEC), devido à ocorrência observada de sintomas psicóticos transitórios em indivíduos após o consumo de Cannabis sativa. Um modelo animal de atenção amplamente utilizado na esquizofrenia é a inibição pré-pulso (IPP) do reflexo de sobressalto. A via neural primária que medeia a resposta IPP é encontrada no tronco encefálico, sendo o colículo inferior (CI) uma estrutura chave neste circuito. O objetivo deste estudo foi avaliar se uma microinjeção de Anandamida (AEA) (50 pmol/0,2 μl), um agonista do receptor CB1, no CI, induziria déficit de IPP, e se esse déficit poderia ser prevenido pelo pré-tratamento com AM251 (50 pmol/0,2 μl), um antagonista do receptor CB1. Clozapina (5mg/kg; i.p.) foi usada como controle positivo para AM251. Foram utilizados 68 ratos Wistar machos pesando 250-320g, divididos em 5 grupos experimentais, sendo: V eículo+V eículo (N=15); V eículo+AEA (N=15); AM251+Veículo (N=15); AM251+AEA (N=15); e CLZ+AEA (N=8). O IPP médio e a amplitude do sobressalto foram analisados usando ANOVA de duas vias com medidas repetidas e ANOVA de uma via, respectivamente. Em caso de significância estatística, foi aplicado o teste post hoc de Bonferroni. O valor de P<0,05 foi considerado significativo. Os resultados obtidos mostraram que o grupo VEI+AEA apresentou déficit de IPP em relação aos cinco grupos, apontando o envolvimento do SEC no CI como crítico na mediação da resposta do IPP em ratos. Além disso, o pré-tratamento com AM251 e CLZ preveniu o déficit de IPP observado no grupo VEI+AEA, indicando não apenas um claro envolvimento do SEC na fisiopatologia da esquizofrenia, mas também apontando para um novo alvo terapêutico para o tratamento desse transtorno. A amplitude da resposta de sobressalto não foi alterada pelos tratamentos, descartando qualquer comprometimento motor dos animais e mostrando o efeito seletivo do AEA no déficit de IPP.