RESUMO
The catecholamines dopamine, norepinephrine and epinephrine were studied in the brains of male and female tropical bats of four species, with different feeding habits (insectivorous, frugivorous, omnivorous and pollen eater). They were trapped in a refuge at 18 degrees 24'24''N, 99 degrees 02'08''W with a mean annual temperature of 25.8 degrees C, in a tropical deciduous forest. The three catecholamines occur in both sexes of all four species, in levels which are statistically different among species as well as between sexes. Dopamine and norepinephrine levels were higher in males than females, but the opposite occurs with epinephrine. These findings suggest that changes in catecholamine levels are intimately involved in the reproductive pattern of the species studied.
Assuntos
Química Encefálica , Catecolaminas/análise , Quirópteros , Caracteres Sexuais , Animais , Comportamento Alimentar , Feminino , Masculino , Clima TropicalRESUMO
The lethality of d-amphetamine was studied in isolated and aggregated mice with and without previous habituation to the physical or to the physical and social environment of chronically aggregated social condition under which the toxic effects of d-amphetamine were tested. In animals without previous habituation to such environments, d-amphetamine's toxicity was greatly enhanced by social aggregation, as reported by several authors in the literature. It was found that mortality in the dose range from 5 to 90 mg/kg is mainly determined by the stimulation due to aggregation. Above 90 mg/kg, the mortalities in single and aggregated mice vary in parallel. Up from this dose, lethality is independent of the external stimulation. Previous experience with house sharing in aggregated conditions reduces aggregation mortality in proportion to the duration of the previous house sharing period.
Assuntos
Aglomeração/fisiopatologia , Dextroanfetamina/toxicidade , Adaptação Psicológica , Animais , Relação Dose-Resposta a Droga , Abrigo para Animais , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Estresse Psicológico/fisiopatologiaRESUMO
The effect of vaginal placement of insulin was ascertained in rats by measuring plasma glucose levels. A rapid and sustained decrease of plasma glucose levels at 30, 60, 90 and 120 minutes after vaginal insulin administration was observed, returning to basal levels by 240 minutes. Thus, rapid insulin absorption was not curtailed by vaginal mucose. The effect was independent of the rat oestrous cycle phase.
Assuntos
Glicemia/análise , Insulina/administração & dosagem , Absorção , Administração Intravaginal , Animais , Estro , Feminino , Insulina/farmacocinética , Insulina/farmacologia , Ratos , Ratos Endogâmicos/metabolismoRESUMO
The fate of 3H-melatonin after its intracerebroventricular administration was studied both in different brain regions and in subcellular fractions. The rate of disappearance of 3H-melatonin from the brain was found to be multiphasic. Forty-eight h after a 3H-melatonin injection, radioactivity was still present in the brain. Nonlinear regression analysis of the data confirmed a very rapid half-life component and (t1/2 = 3.04 min) a slower one (t1/2 = 36 min). We also found a much slower component (t1/2 = 24 h), however. Considerable metabolism of melatonin was detected since only 36.5% of administered radioactivity remained as melatonin at 45 min. The subcellular distribution of the radioactivity present in the brain at all times studied showed that a major proportion of the radioactivity remained in the cytosol and respectively decreasing proportions in the 900g pellet, mitochondrial pellet, and the microsomes. The radioactivity remaining in the cytosol at 45 min was found to coelute with a macromolecule that was resolved by gel filtration and could be displaced by previous melatonin administration. Purified nuclei retained 0.71% of the radioactivity at 45 min; of this total, 73% was KCl extractable. Our data suggest the presence of a binding site in the cytosol and in the nucleus. The presence of 3H-melatonin up to 48 h after its administration may account for melatonin's long-term effects on brain function.
Assuntos
Encéfalo/metabolismo , Melatonina/farmacocinética , Animais , Sítios de Ligação , Injeções Intraventriculares , Masculino , Melatonina/administração & dosagem , Ratos , Ratos Endogâmicos , Frações Subcelulares/metabolismo , Distribuição TecidualRESUMO
Dopamine, norepinephrine, 5-hydroxytryptamine, and 5-hydroxyndoleacetic acid concentrations were measured in human seminal plasma and follicular fluid of healthy fertile individuals and in seminal plasma of azoospermic patients. All these substances were unevenly distributed in the male and female reproductive tract fluids. The highest monoamine (MA) concentration was observed for azoospermic seminal plasma followed by normal seminal plasma and follicular fluid. The differences in MA content were statistically significant. The occurrence of MA in human follicular fluid supports the suggestion of several authors that MA are involved in the regulation of the acquisition of the fertilizing ability of the sperm in female reproductive tract. However, the presence and uneven distribution of each MA in male and female fluids testify the complexity of the MA function in regulating the fertilizing ability spermatozoa