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Efeitos cr?nicos do aumento da libera??o de serotonina, da inibi??o da recapta??o pr?-sin?ptica de serotonina e da estimula??o de receptor 5-HT1A, na sede e no apetite por s?dio em ratos / Chronic effects of increased release of serotonin, inhibiting pre-synaptic reuptake of serotonin and the stimulation of 5-HT1A receptor in the thirst and the appetite for sodium in ratsNunes, Ana Paula de Magalh?es 13 March 2009 (has links)
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Previous issue date: 2009-03-13 / Funda??o Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / In order to investigate the hypothesis of the influence of serotonergic system on
the control of dipsogenic and sodium appetite, we examined the effects of chronicallytreated
rats with the brain serotonin releaser, fenfluramine, the 5-HT1A agonist, 8-OHDPAT
and the selective serotonin re-uptake inhibitor, sertraline. Animals treated with 5-
HT1A agonist and brain serotonin releaser were sodium depleted and then their fluids
intake analyzed. The first group decreased significantly the salt intake response while
the second group intensified the sodium appetite 2 weeks after the first administration of
fenfluramine. The water consumption was not altered in none of the groups when
compared to their respective controls. Sodium-depleted animals that were treated with
sertraline showed a more intense natriorexigenic response. On the other hand, water
deprivation induced a lower water intake in SERT-treated rats than the controls.
Osmotic simulation evoked a dipsogenic response significantly lower in SERT group.
Fluids and food deprivation induced a weak dipsogenic response in SERT treated-rats
compared to controls but without difference on saline intake. An increased urinary
density and decreased plasma sodium levels in SERT-treated rats correlated with the
highest plasma vasopressin and oxytocin levels at the 3rd week post-treatment. The
obtained results in chronically-treated rats with the 5-HT1A agonist and the brain
serotonin releaser, suggest that the alteration on the brain serotoninergic activity
influences the sodium appetite expression, possibly after 5-HT1A autoreceptor
desensitization produced by 8-OH-DPAT or brain serotonin depletion achieved with
fenfluramine treatment. The results of chronically-treated rats with sertraline, constitute
the first evidence of alterations on the threshold for thirst and sodium appetite response
in SERT-chronically-treated rats. These alterations possibly are consequence of the
hyponatremia provided by inappropriate secretion of AVP and OT. / Para investigar a hip?tese da influ?ncia do status do sistema seroton?rgico no
controle da resposta dipsog?nica e do apetite ao s?dio, analisamos os efeitos de ratos
tratados cronicamente com um liberador cerebral de serotonina, fenfluramina, um
agonista 5-HT1A, 8-OH-DPAT e um inibidor da recapta??o pr?-sin?ptica de serotonina,
sertralina (SERT). Animais tratados com agonista 5-HT1A e com liberador cerebral de
serotonina, foram submetidos a deple??o de s?dio e, posteriormente, a ingest?o de
fluidos foi aferida. O primeiro grupo diminuiu significativamente a ingest?o de salina
hipert?nica, enquanto o segundo grupo intensificou o apetite ao s?dio 2 semanas ap?s o
?n?cio do tratamento com fenfluramina. O consumo de ?gua n?o foi alterado em nenhum
dos grupos, quando comparados aos seus respectivos grupo controle. Os animais
tratados cronicamente com SERT que sofreram deple??o de s?dio, obtiveram uma
intensa resposta natriorexig?nica. Por outro lado, a priva??o de ?gua induziu uma menor
ingest?o de ?gua em ratos tratados cronicamente com SERT quando comparado-os aos
do grupo controle. O est?mulo osm?tico evocou uma resposta dipsog?nica
significativamente menor no grupo SERT. A priva??o de fluidos e de alimentos induziu
uma baixa resposta dipsog?nica em ratos tratados com SERT quando comparados aos
controles, mas sem diferen?a significativa na ingest?o de salina hipert?nica. O aumento
da densidade urin?ria em ratos tratados com SERT correlaciona-se com os maiores
n?veis plasm?ticos do horm?nio anti-diur?tico e ocitocina na 4? semana p?s-tratamento.
Os resultados obtidos em ratos tratados cronicamente, com o agonista 5-HT1A e com o
liberador cerebral de serotonina, sugerem uma poss?vel altera??o da atividade cerebral
serotonin?rgica, influenciando assim a express?o do apetite ao s?dio, pois
possivelmente ocorreu uma dessensibiliza??o de autoreceptores 5-HT1A com o
tratamento com 8-OH-DPAT, e deple??o cerebral de serotonina, obtida com o
tratamento com fenfluramina. Os resultados relativos aos animais tratados cronicamente
com sertralina, constituem as primeiras evid?ncias de altera??o no limiar de sede e de
apetite ao s?dio. Essas altera??es s?o possivelmente conseq??ncia da hiponatremia
gerada pela secre??o inapropriada de ADH e OT.
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Influ?ncia de diferentes doses de cipionato de estradiol nas altera??es hidroeletrol?ticas de ratas ovariectomizadas. / Influence of different doses of estradiol cipionate on the hidroelectrolytic challenges of female ovariectomized rats.MENEZES, Veronica Cristina Lopes 30 July 2015 (has links)
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Previous issue date: 2015-07-30 / CAPES / The distribution of estrogen receptors in brain structures that are envolved in the hidroelectrolyte balance such as the lamina terminalis (LT), subfornical organ (SFO) and dorsal raphe nucleus (DRN) demonstrated that estradiol can modulate important responses in body fluids. In the literature experimental data support that estrogen can increase the triptofan-hydroxilase type 2 , the main enzyme for the serotonin synthesis. The primary question here is whether or not differences in the baseline or stimulated intake are a function of different levels of circulating gonadal hormones in female ovariectomized rats. Female Wistar intact rats (~230 g) were previously aclimated in metabolic cages during 5 days and ad libitum access to water and hypertonic saline (1.8%) bottles and food. Room temperature was maintained at 22?2 ?C with 12:12 h light-dark cycle (lights off at 19:00). Rats were anesthetized with intraperitoneal injections of a mixture of ketamine (75 mg/kg) and xylazine (5 mg/kg) and then bilaterally ovariohysterectomized. There were four experimental groups: OVX (replaced with corn oil), 2,5 ?g/kg (E2 2,5), 10,0 ?g/kg (E2 10,0) and 40,0 ?g/kg (E2 40,0), daily during seven days, s.c. After 24 h of the surgery the hormonal replacement initiated (estradiol cypionate, EC, Pfizer, Animal Health). We did three experimental protocols: baseline evaluations, sodium depletion and fluid replacement. The estrogen replacement exibitted a dose dependent effect in the following parameters under basal conditions: daily body weight, daily urinary volume and daily food intake. After sodium depletion there were no difference in the urinary volume after 2 and 24 hours of the experiment. But after fluid reposition we observed a dose dependent effect in the ingestive behaviour of water and hypertonic saline intake in sodium depleted and control animals. Our data support that estradiol can alter the natriorexigenic and dipsogenic responses especially after sodium depletion depending of the estrogenic status. / A distribui??o de receptores estrog?nicos em estruturas centrais envolvidas na regula??o da homeostase hidroeletrol?tica como o ?rg?o vasculoso da l?mina terminal, n?cleo subfornicial, n?cleo dorsal da rafe indica que o estradiol pode atuar nessas estruturas em resposta a altera??es nos fluidos corporais. Nosso objetivo foi verificar se a reposi??o hormonal pode influenciar de maneira concentra??o-dependente o status hidroeletrol?tico e neuroend?crino de ratas castradas com reposi??o hormonal em diferentes doses de forma comparativa. Ratas Wistar (~230 g) foram previamente adaptadas, por 5 dias, em gaiolas metab?licas, com acesso ad libitum aos bebedouros volum?tricos de ?gua e salina hipert?nica e ao alimento, sendo mantidas sob ciclo claro-escuro de 12 horas em sala com temperatura controlada em 22??2 ?C. Ao final da adapta??o, as ratas previamente anestesiadas com cetamina (75 mg/kg) e xilazina (5 mg/kg) foram submetidas ? cirurgia de ovariectomia bilateral. Os animais foram divididos em 4 grupos: OVX, reposi??o com ?leo de milho), repostos com ?leo de milho cipionato de estradiol (E2) 2,5 ?g/kg (E2 2,5), 10,0 ?g/kg (E2 10,0) e 40 ?g/kg (E2 40,0). O tratamento de reposi??o foi feito pela via subcut?nea, diariamente durante 7 dias tendo sido iniciado no dia seguinte ? cirurgia. Foram realizados tr?s protocolos experimentais: avalia??o sob condi??es basais, deple??o de ?ons s?dio e reapresenta??o de fluidos. Neste estudo o estradiol apresentou efeito dose dependente nos seguintes par?metros sob condi??es basais: peso corporal di?rio, volume urin?rio di?rio, ingest?o de alimento di?rio. Ap?s deple??o de s?dio n?o houve diferen?a em rela??o ao volume urin?rio de 2 e de 24 horas ap?s o experimento. No entanto ap?s a reapresenta??o dos fluidos houve efeito dose-dependente no comportamento ingestivo de ?gua e de salina hipert?nica tanto nos animais depletados de s?dio quanto nos animais controles.Os dados suportam que o estradiol modula o comportamento ingestivo dos animais sob condi??es basais e ap?s a deple??o de s?dio.
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