Navegando por Palavras-chave "neurotransmission"
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- ItemSomente MetadadadosDecreased noradrenergic and serotonergic reactivity of vas deferens of newborn rats from mothers treated with the serotonin reuptake inhibitor fluoxetine during pregnancy and breast-feeding(Elsevier B.V., 2007-11-10) Pereira, Janaina D.; Caricati-Neto, Afonso [UNIFESP]; Jurkiewicz, Aron; Jurkiewicz, Neide H.; Universidade Federal de São Paulo (UNIFESP)Female Wistar rats were treated with the serotonin reuptake inhibitor fluoxetine (10 mg/kg/i.p/day), during pregnancy and breast-feeding, for the study of the corresponding newborn rats. At the end of the prewcaning period, the 30-day old litters had their vas deferens removed for testing peripheral sympathetic reactivity, through the following experiments in vitro: (a) concentration-contraction curves for serotonin and for the adrenergic agonists noradrenaline, phenylephrine, clonidine and dopamine or for the indirect agonist tyramine (b) contractions induced by electric field stimulation, as an indicator of sympathetic neurotransmission (c) release of endogenous noradrenaline, measured by real-time determinations on HPLC (d) Ca+2 time-contraction curves, to check for changes on Ca+2 translocation. Our results showed that the affinity (pD(2)) for serotonin was strikingly decreased by about 1.5 log units. the pD2 for adrenergic agonists was decreased by about 0.5 log units, except for dopamine and clonidine. the maximum effects and intrinsic activity were decreased only for dopamine. On the other hand, the response to Ca+2 and the release of noradrenaline from nerve terminals were not modified. in additional experiments, the mother's body weights were measured, showing a decrease during gestation and a recovery during lactation while the offspring's weights were lower than controls. It is concluded that, besides the alterations on body weights, changes on noradrenergic and serotonergic mechanisms were observed and persisted in the newborn, at least one month after parturition. (c) 2007 Elsevier Inc. All rights reserved.
- ItemSomente MetadadadosFunctional properties of agmatine in rat vas deferens(Elsevier B.V., 1996-07-04) Jurkiewicz, N. H.; doCarmo, L. G.; Hirata, H.; Santos, W. D.; Jurkiewicz, A.; Universidade Federal de São Paulo (UNIFESP)Experiments were performed with rat vas deferens to verify whether agmatine, an endogenous ligand for adrenoceptors and imidazoline receptors, can influence sympathetic neurotransmission, with respect to contractions induced by transmural nerve stimulation, contractions induced by exogenous noradrenaline, and overflow of endogenous noradrenaline. It was shown that agmatine (a) caused a dose-dependent potentiation of electrically induced twitches, up to about 70% in relation to controls, (b) shifted to the right the inhibitory concentration-response curves for clonidine on electrically induced twitches, indicating competitive antagonism at presynaptic ol-adrenoceptors, with a pA(2) value of 4.12 +/- 0.10, (c) shifted to the right the concentration-response curves for noradrenaline-induced contractions, indicating competitive antagonism at postsynaptic alpha-adrenoceptors as well, with a pA(2) value of 4.03 +/- 0.10, and (d) caused a dose-dependent increase of KCl-induced overflow of noradrenaline, up to about 90% in relation to controls. It is concluded that agmatine has multiple effects on sympathetic neurotransmission in rat vas deferens.
- ItemAcesso aberto (Open Access)Identificação de genes diferencialmente expressos nas vias de neurotransmissão cerebral de camundongas anovulatórias(Universidade Federal de São Paulo (UNIFESP), 2013-11-27) Azevedo Junior, Marcos Antonio [UNIFESP]; Silva, Ismael Dale Cotrim Guerreiro da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Women with pre-eclampsia may present thrombocytopenia, a severe sign of the disease. The aim of this study was to evaluate the platelet aggregation capacity in pre-eclampsia women. Platelet function was studied in 20 non-pregnant women, 25 normotensive pregnant women, and 20 pre-eclampsia women. Pre-eclampsia was diagnosed by association of hypertension (? 140 x 90 mmHg) and proteinuria (? 300 mg per 24 hours). Platelet was counted in an hemocytometric chamber, and thrombocytopenia was considered when platelet number was lower than 186x103/?l, that represents the average minus two standard deviation of non-pregnant women values. The platelet aggregation was measured in an aggregometer after ADP and collagen agonists stimulation. The comparison among the groups studied was done by one way analysis of variance followed by the Tukey test and P values than 5% were taken to be significant. A significant difference was seen in platelet count among non-pregnant (284+49x103/?l) and pregnant women (normotensive: 219+58x103/??l versus pre-eclampsia: 211+54x103/??l). The platelet aggregation induced by ADP was significantly higher in non-pregnant women (87.7+6.1) than normotensive pregnant women (73.6+14.9) and pre-eclamptic women (53.8+21.7), while the values from this last group was lower than in the normotensive pregnant grou Platelet aggregation in response to collagen stimulation was similar among non-pregnant (90.4+5.4) and normotensive pregnant women (83.4+11.1) and lower in pre-eclamptic women (67.7+23.4). In pre-eclamptic women the platelet aggregation induced by ADP and collagen was similar in the groups with or without thrombocytopenia. The results suggest that pre-eclamptic women platelets have weaker ability to aggregate independent of the number. Thus, platelet function may be altered even when their number is normal in pre-eclampsia.
- ItemSomente MetadadadosSympathetic neurotransmission in the rat testicular capsule: Functional characterization and identification of mRNA encoding alpha(1)-adrenoceptor subtypes(Elsevier B.V., 2006-08-14) Jurkiewicz, Neide Hyppolito; Caricati-Neto, Afonso; Verde, Luciana Ferreira; Avellar, Maria Christina W.; Reuter, Hayde Rezende; Jurkiewicz, Aron; Universidade Federal de São Paulo (UNIFESP)The rat testicular capsule is a thin tissue surrounding the testis, whose precise function is still unknown. We have studied the contractile effects of electrical field stimulation, noradrenaline, and the blockade by antagonists of adrenergic receptors, in order to characterize sympathetic neurotransmission, and adrenoceptor subtypes. in addition, reverse transcription polymerase chain reaction (RT-PCR) assays were made to check for the expression of the three known subtypes of alpha(1)-adrenoceptors. the effects of electrical field stimulation (2 to 20 Hz, 1 ms, 60 V) were almost totally abolished by depletion of neuronal noradrenaline storage with reserpine (10 mg/Kg), but not by the purinergic receptor antagonist suramin (10(-5) M), indicating that noradrenaline, but not ATP, was involved in contractions. the selective alpha(1)-adrenoceptor antagonist prazosin (10(-7) M) was more effective than the selective alpha(2)-adrenoceptor antagonist idazoxan (10-7 M) to inhibit contractions induced by electrical field stimulation, pointing out a major involvement of alpha(1)-adrenoceptor. When noradrenaline was used instead of electrical field stimulation, it showed a high potency (pD(2)=7.9). Noradrenaline-induced contractions were competitively blocked by the selective alpha(1A)-adrenoceptor antagonists WB 4101 (pA(2)=8-88), phentolamine (pA(2)=8.39) and by the alpha(1B)-adrenoceptor antagonist spiperone (pA(2)=8.57), indicating the presence of functional alpha(1A)- and alpha(1B)-adrenoceptors. in addition, contractions were not blocked by the selective alpha(1D)-adrenoceptor antagonist BMY 7378 (up to 10(-6) M), while selective alpha(2)-adrenoceptor ntagonists showed low pA(2) values (yohimbine, 7.25 and idazoxan, 7.49), suggesting a minor role, if any, for alpha(1D)- and alpha(2)-adrenoceptors. To check the proportionate role of alpha(1A)- and alpha(1B)-adrenoceptors, we blocked alpha(1B)-adrenoceptors with chloroethylclonidine (CEC, 30 mu M, 45 min), that reduced the maximal effect of noradrenaline by about 60%. the remnant CEC-insensitive noradrenaline contraction was assumed to be unrelated to alpha(1B)-adrenoceptor, and was inhibited by 5-methyl-urapidil (pA(2) = 8.94) and by the Ca2+ channel blocker nifedipine (3 mu M), confirming the involvement of alpha(1A)-adrenoceptors. the presence of mRNA encoding alpha(1A)- and alpha(1B)-adrenoceptor was also shown on RT-PCR assays. Unexpectedly, alpha(1D)-transcripts were also detected in these assays. Taken together, our results show that ATP co-transmission could not be detected, and that neurotransmission involves the interaction of noradrenaline with both alpha(1A)- and alpha(1B)-, but not with alpha(1D)- or alpha(2)-adrenoceptor. the fact that the functional U I D-adrenoceptor could not be detected in spite of the presence of the corresponding mRNA, remains to be investigated. (c) 2006 Elsevier B.V All rights reserved.
- ItemSomente MetadadadosUse of transgenic (knockout) mice reveals a site distinct from the alpha(2A)-adrenoceptors for agmatine in the vas deferens(Polish Acad Sciences Inst Pharmacology, 2009-03-01) Santos, Wilson da Costa; Garcez-do-Carmo, Lucia [UNIFESP]; Silva, Eliane Cristina da [UNIFESP]; Pascual, Ricardo de; Jurkiewicz, Neide Hyppolito [UNIFESP]; Jurkiewicz, Aron [UNIFESP]; Gandia, Luis; Universidade Federal Fluminense (UFF); Universidade Federal de São Paulo (UNIFESP); Fac MedThe inhibitory effect of agmatine on electrically induced contractions was studied in vas deferens of Adra 2a transgenic mice lacking alpha(2A)-adrenoceptors. Agmatine and clonidine caused a concentration-dependent inhibition of twitches. However, while agmatine showed a similar pIC(50) value in control and transgenic mice, the pIC(50) value for clonidine was about 30-fold lower in knockout mice. In both strains, yohimbine shifted the curve for clonidine, but not for agmatine, even when a 100-fold higher concentration of yohimbine was employed. Our results indicate that inhibition by agmatine in mouse vas deferens is not simply due to interactions with alpha(2)-adrenoceptors in our experimental conditions.