RESUMO
This study evaluated the effects of thiamine pyrophosphate (PPT) on the biochemical profiles of full-term rabbit foetuses that were subjected to experimental ischemia followed by 24h reperfusion. A total of 16 gestating rabbit dams were divided into two groups, one of which was treated by administering PPT and subjected to a process ischemia. During this interval, fetal blood samples were drawn from each dam (in the ischemia group) at 0, 15 and 45min. Ischemia for 15 and 45min was not associated with changes in lactate levels of the Ischemia group foetuses. However, in the foetuses in the reperfusion groups without PPT lactate levels were significantly higher after 15 and 45min of arterial occlusion compared to time zero. These results demonstrate that PTT alters some acute and some longer-term biochemical outcomes of uterine ischemia perhaps important in preserving energy metabolism under hypoxic conditions.
Assuntos
Feto/efeitos dos fármacos , Isquemia/metabolismo , Substâncias Protetoras/farmacologia , Tiamina Pirofosfato/farmacologia , Útero/irrigação sanguínea , Animais , Glicemia/análise , Cálcio/metabolismo , Feminino , Feto/metabolismo , Concentração de Íons de Hidrogênio , Hipóxia/metabolismo , Ácido Láctico/sangue , CoelhosRESUMO
Our aim was to study the specific role of the postsynaptic D(1) receptors on dopaminergic response and analyze the metabolized dopamine (DA) in the rat striatum. We used male Wistar rats to evaluate the effects of different doses of a D(1) agonist (SKF-38393) and a D(1) antagonist (SCH-23390), and their co-administration. The levels of DA and L-3, 4-dihydroxyphenylacetic acid (DOPAC) were measured using high performance liquid chromatography. The systemic injection of SKF-38393 alone at 1, 5 and 10 mg/kg did not alter the DA and DOPAC levels or the DOPAC/DA ratio. In contrast, injection of SCH-23390 alone at 0.25, 0.5 and 1 mg/kg significantly increased the DA and DOPAC levels, as well as the DOPAC/DA ratio, compared with the respective control groups. The co-administration of SCH-23390+SKF-38393 did not alter the DA or DOPAC levels, but it did significantly inhibit the SCH-23390-induced increase of the DA and DOPAC levels. The SCH-23390+SKF-38393 and the SCH-23390-only groups showed an increase in the DOPAC/DA ratio. The co-administration of SCH-23390+PARGYLINE significantly decreased the DOPAC levels and the DOPAC/DA ratio compared with the control and SCH-23390 groups. Taken together, our results showed that selective inhibition with SCH-23390 produced an increase in metabolized DA via striatal monoamine oxidase. These findings also contribute to the understanding of the role of postsynaptic D(1) receptors in the long-loop negative feedback system in the rat striatum.
Assuntos
Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Receptores de Dopamina D1/antagonistas & inibidores , 2,3,4,5-Tetra-Hidro-7,8-Di-Hidroxi-1-Fenil-1H-3-Benzazepina/administração & dosagem , 2,3,4,5-Tetra-Hidro-7,8-Di-Hidroxi-1-Fenil-1H-3-Benzazepina/farmacologia , Animais , Benzazepinas/administração & dosagem , Benzazepinas/farmacologia , Corpo Estriado/metabolismo , Agonistas de Dopamina/farmacologia , Antagonistas de Dopamina/farmacologia , Masculino , Pargilina/administração & dosagem , Ratos , Ratos WistarRESUMO
Se estudió la sensibilidad de la vía auditiva a través del registro de los potenciales auditivos de tallo cerebral en 10 anfibios sanos de la especie Rana catesbiana. Las respuestas auditivas se efectuaron a 70, 50, 40 y 30 dB NA, en dos grupos de diferente peso. El primero de 17 a 27 gr y el otro grupo de 36 a 86.5 gr, los electrodos fueron insertados subcutáneamente y la estimulación fue por clicks en campo libre dentro de una cámara sonoamortiguada. A 70 dB las respuestas fueron de dos ondas en los primeros milisegundos, a 50 dB la onda II se separó en dos subcomponentes (IIa y IIb). El umbral electrofisiológico se estableció en 40 dB