by Priscilla, Ka-Yee Chan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 77-100). / Abstract also in Chinese. / ACKNOWLEDGEMENTS --- p.4 / ABSTRACT --- p.5 / ABSTRACT (Chinese) --- p.7 / PUBLICATION --- p.8 / ABBREVIATION --- p.9 / Chapter CHAPTER 1 --- INTRODUCTION --- p.10 / Chapter 1.1 --- Overview of the study --- p.10 / Chapter 1.2. --- Substantia nigra pars reticulata (SNR) --- p.12 / Chapter 1.2.1 --- SNR and the basal ganglia / Chapter 1.2.2 --- GABA neurotransmission in SNR / Chapter 1.2.3 --- SNR and epilepsy / Chapter 1.3 --- GABAb receptors --- p.18 / Chapter 1.3.1 --- GABA receptors / Chapter 1.3.2 --- GABAb receptors and their classification / Chapter 1.3.3 --- Agonists and antagonists of GABAb receptor / Chapter 1.3.4 --- Distribution of GAB AB receptor / Chapter 1.3.5 --- GABAb receptors in epilepsy and the involvement of SNR / Chapter 1.4 --- Cannabinoid receptors --- p.24 / Chapter 1.4.1 --- Cannabinoid receptors and their classification / Chapter 1.4.2 --- Agonists and antagonists of cannabinoid receptor / Chapter 1.4.3 --- Distribution of cannabinoid receptors / Chapter 1.4.4 --- Cannabinoid receptors in epilepsy and the involvement of SNR / Chapter CHAPTER 2 --- METHODS --- p.31 / Chapter 2.1 --- Brain slice preparation and maintenance --- p.31 / Chapter 2.2 --- Experimental set-up --- p.32 / Chapter 2.2.1 --- Visualization of neurones / Chapter 2.2.2 --- Electrophysiological recordings / Chapter 2.2.3 --- Evoked stimulation / Chapter 2.2.4 --- Drug preparation and administration / Chapter 2.3 --- Identification of GAB A and dopamine neurones --- p.36 / Chapter 2.4 --- Data analysis --- p.37 / Chapter 2.4.1 --- Construction of dose-response curve / Chapter 2.4.2 --- Analysis of synaptic currents / Chapter 2.4.3 --- Statistics / Chapter CHAPTER 3 --- RESULTS --- p.39 / Chapter 3.1 --- Basic characteristics of IPSCs in SNR --- p.39 / Chapter 3.1.1 --- Spontaneous and miniature IPSCs / Chapter 3.1.2 --- Evoked IPSCs / Chapter 3.2 --- GABAb receptors in SNR --- p.42 / Chapter 3.2.1 --- Postsynaptic GABAb receptors in SNR neurones / Chapter 3.2.1.1 --- Baclofen-activated postsynaptic response / Chapter 3.2.1.2 --- Effects of GABAb receptor antagonist on IPSCs / Chapter 3.2.2 --- Presynaptic GABAb receptors / Chapter 3.2.3 --- Effects of GAB A uptake blocker / Chapter 3.3 --- Cannabinoid receptors in SNR --- p.51 / Chapter 3.3.1 --- Postsynaptic cannabinoid receptors in SNR neurones / Chapter 3.3.2 --- Presynaptic action of cannabinoids / Chapter CHAPTER 4 --- DISCUSSION and CONCLUSION --- p.55 / Chapter 4.1 --- General properties of IPSCs --- p.55 / Chapter 4.2 --- GABAb receptors in SNR neurones --- p.58 / Chapter 4.2.1 --- Postsynaptic GABAB receptors in SNR neurones / Chapter 4.2.2 --- GABAb component in spontaneous and evoked IPSCs / Chapter 4.2.3 --- Presynaptic GABAb receptors in SNR / Chapter 4.2.4 --- Role of GABA uptake / Chapter 4.3 --- Cannabinoid receptors in SNR neurones --- p.67 / Chapter 4.3.1 --- Postsynaptic cannabinoid receptors in SNR neurones / Chapter 4.3.2 --- Presynaptic cannabinoid receptors in SNR / Chapter 4.4 --- SNR GABAb and cannabinoid receptors - their role in epilepsy --- p.72 / Chapter 4.5 --- Concluding remarks and future direction --- p.75 / REFERENCES --- p.77

Diss. Linköping : Univ., 2003. / Härtill 4 uppsatser.

Orientador: Eros Antonio de Almeida / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-20T19:20:03Z (GMT). No. of bitstreams: 1 RamirezNunez_WilsonRanu_D.pdf: 1943462 bytes, checksum: 1cb7938d9770774612068d3048db5b0e (MD5) Previous issue date: 2012 / Resumo: O esvaziamento gástrico (EG) consiste na transferência ordenada do conteúdo do estômago para o duodeno, Situações patológicas como alterações hemodinâmicas modificam a velocidade do E.G. e função motora do trato gastrointestinal. O infarto do miocárdio determina retarde do E.G. em ratos, possivelmente pelo estresse causado pela ligadura da artéria coronária. O sistema nervoso central (SNC) afeta as funções motora e secretora gastrintestinais, frente a uma situação de estresse existe aumento da retenção gástrica (RG) induzindo o retarde do E.G. O sistema parassimpático pode estar envolvido neste fenômeno. Por outro lado o sistema simpático controla o E.G., interrompendo a motilidade e a secreção, frente a uma situação de estresse como a do infarto do miocárdio o retarde do E.G., pode estar relacionado à atuação desse sistema. O objetivo deste trabalho foi Avaliar complacência gástrica (CG) em ratos submetidos a infarto recente do miocárdio, participação do nervo vago, sistema nervos simpático, efeito da injeção intra-cerebro-ventricular de GABAb e efeito da lesão do núcleo paraventricular no retarde do EG observado no infarto recente do miocárdio em ratos. Utilizados ratos Wistar, machos, entre 220 - 300g, adaptados ás condições do laboratório, divididos em 3 grupos: grupo INF; grupo SH e grupo NA. Infarto realizado por ligadura da artéria coronária descendente anterior esquerda. Animais após cirurgia permaneceram em jejum alimentar recebendo água ad libitum. Vinte e quatro horas após foi avaliado EG de 1,5 ml/100g de peso do animal de uma refeição de prova (RP) salina marcada com fenol vermelho. EG foi avaliado indiretamente, através da determinação da % de retenção gástrica (RG) da RP, 10 min. após administração orogástrica. Resultados mostraram que para o estudo da complacência gástrica não houve diferença significativa de pressão intragástrica entre os três grupos, nos três pontos de medida da pressão intragástrica (PIG) e em complementação as CGs não apresentaram diferenças significativas quando comparados entre si. No estudo da Vagotomia subdiafragmatica houve diferença significativa das RG (%) entre os subgrupos SH+Sh vs SH+Inf, o subgrupo Vgx+Inf apresentou diferença significativa em relação ao subgrupo SH+Inf e não diferiu do subgrupo Vgx+Sh. Para o estudo do efeito da injeção intra-cerebro-ventricular de GABAb houve diferença significativa entre os grupos SH+Sal e SH+Bac e Inf+Sal e Inf+Bac. No estudo da Simpatectomia química, grupo Inf+Sal apresentou diferença significativa quando comparados aos ratos SH+Sal, e grupo Inf+Pra com grupo SH+Sal não apresentaram diferenças significativas. O grupo Inf+Pra e Inf+Sal apresentaram diferença significativa e ratos SH+Pra e SH+Sal apresentaram diferença significativa quando comparados, No estudo da lesão do Núcleo paraventricular houve diferença significativa das RG (%) entre os subgrupos SH+Sh vs SH+Inf, os grupos PVN+Inf e SH+Inf apresentaram diferença significativa. Conclusões: 1) infarto recente do miocárdio não induz modificações no tônus gástrico em ratos, 2) Existe participação do nervo vago no retarde do EG causado pelo infarto recente do miocárdio, 3) Retardo EG mostrado pelos ratos infartados tem participação, pelo menos em parte, dos receptores alpha-1 adrenérgicos do sistema nervos simpático. 4) Existe participação do núcleo paraventricular no retardo do EG induzido pelo infarto recente do miocárdio / Abstract: Gastric emptying (GE) is the orderly transfer of stomach contents into the duodenum, pathological situations as hemodynamic changes modify GE speed and motor function of the gastrointestinal tract. Myocardial infarction determines GE delayed in rats, possibly due to stress caused by coronary artery ligation. Central nervous system (CNS) affects gastrointestinal secretory and motor functions, in a stressful situation there is increased gastric retention (GR) inducing GE delay. Parasympathetic system may be involved in this phenomenon. On the other hand sympathetic nervous system controls GE, disrupting motility and secretion, compared to a stressful situation such as myocardial infarction, GE delay, may be related to performance of this system. The objective of this study was to evaluate gastric compliance (GC) in rats submitted to recent myocardial infarction, involvement of vagus nerve, sympathetic nervous system, intra-cerebro-ventricular of GABAb injectin effect and paraventricular nucleus lesion effect on GE delay observed in recent myocardial infarction in rats. Used male Wistar rats, between 220-300g, adapted to laboratory conditions, divided into three groups: INF, SH and NA groups. Infarction performed by left anterior descending coronary artery ligation. After surgery, animals were fasted receiving water ad libitum. Twenty four hours after was evaluated GE of 1.5ml/100g body weight of a saline test meal (TM) labeled with red phenol. GE was indirectly estimated by determining % of gastric retention (GR) of test meal. 10 min. after orogastric administration. Results showed that gastric compliance study there was no significant difference in intragastric pressure between the three groups, in the three points of measurement of intragastric pressure (IGP) and complementation in GC showed no significant differences when compared with each other. In subdiaphragmatic vagotomy study, significant difference of GR (%) between subgroups SH+Sh vs SH+Inf, subgroup Vgx+Inf significant difference in the subgroup SH+Inf and did not differ in subgroup Vgx+Sh. To study the effect of intracerebroventricular injection of GABAb significant difference between groups SH+Sal vs SH+Bac and Inf+Sal vs Inf+Bac. To study the chemical simpatectomy by prazosin, the Inf+Sal group showed significant difference when compared to SH+Sal rats, and the group Inf+Pra with SH+Sal group showed no significant difference. The group Inf+Pra and Inf+Sal showed significant differences and the rats SH+Pra and SH+Sal showed significant difference when compared, for the study of the lesion of paraventricular nucleus of GR significant difference (%) between subgroups SH+Sh vs SH+Inf, the group PVN+Inf and SH+Inf showed significant difference. Conclusions: 1) recent myocardial infarction does not induce changes in gastric tone in rats, 2) there is involvement of the vagus nerve in GE delay caused by recent myocardial infarction, 3) GE delayed in infracted rats have participation, at least in part, of alpha-1 adrenergic receptors of the sympathetic nervous system, 4) there is participation of the paraventricular nucleus of GE delayed induced by recent myocardial infarction / Doutorado / Ciencias Basicas / Doutor em Clínica Médica