A dopamine mechanism is implied in the acquisition and expression of amphetamine and stress-induced effects observed in the lymphocyte subpopulations.

Drugs of abuse and stress are associated with changes in circulating cell populations and reductions in cell-mediated immune responses. The main goal of this study was to determine the influence of repeated and acute d-amphetamine treatments on the foot-shock stress-induced effects on the peripheral lymphocyte subpopulations, and the involvement of a dopamine mechanism in the development and expression of this phenomenon. Wistar rats received an acute (5 mg/kg/day i.p.) or a repeated (2 mg/kg/day i.p. during 9 days) amphetamine treatment, and were exposed to a foot-shock stress (1 mA, 3 s) 4 days after the last amphetamine injection. Another group was administered with haloperidol (1 mg/kg/day i.p.) 15 min previous to each daily amphetamine injection or previous to the foot-shock stress session. Then, blood cells stained with monoclonal antibodies against CD3-FITC, CD8-PE and CD4-Cy-Chrome, and against CD161a-FITC, CD3-PE, and CD45RA-Cy-Crhome, were analyzed by multiparameter flow cytometry. The exposure to a foot-shock stress induced a decrease in the absolute number of peripheral lymphocytes, as well as in CD4+ and CD8+ T-cells and B-cells in acute and repeatedly amphetamine-treated rats, whereas the NK-cell population remained unchanged. Haloperidol administration previous to each drug administration or the foot-shock stress session reversed these effects. This study provides strong evidence that dopamine can play a more general role in the influence of amphetamine on the stress-induced effects on the lymphocyte subsets.

Neurological maturation in the first semester of life in small for gestation age infants.

Our aim was to evaluate the acquisition of neuropsychomotor development marks in small for gestational age infants during the first six months of life. A non-controlled cross-section study with thirty full-term newborn small for gestational age infants was performed in a University Hospital in the Southern region of Brazil. These infants were followed up during six months and compared with literature data regarding adequate to gestational age newborn babies. Anthropometric data, epidemiologic characteristics, neurological exam and neuropsychomotor evolution were analyzed. There were significant variations in the acquisition of abilities, as the cephalic support at 3 months of age and delay in lalation. In other aspects, babies born small for gestational age evoluted in a similar way as newborn ones standards. It is suggested that case control studies are performed aiming at deepening the analysis of these studies.

Neurological maturation in the first semester of life in small for gestation age infants

Our aim was to evaluate the acquisition of neuropsychomotor development marks in small for gestational age infants during the first six months of life. A non-controlled cross-section study with thirty full-term newborn small for gestational age infants was performed in a University Hospital in the Southern region of Brazil. These infants were followed up during six months and compared with literature data regarding adequate to gestational age newborn babies. Anthropometric data, epidemiologic characteristics, neurological exam and neuropsychomotor evolution were analyzed. There were significant variations in the acquisition of abilities, as the cephalic support at 3 months of age and delay in lalation. In other aspects, babies born small for gestational age evoluted in a similar way as newborn ones standards. It is suggested that case control studies are performed aiming at deepening the analysis of these studies.

Nosso objetivo foi avaliar a aquisição de marcos do desenvolvimento neuropsicomotor em crianças nascidas pequenas para a idade gestacional, durante o primeiro semestre de vida. Foi realizado um estudo de coorte não controlada, com 30 recém-nascidos pequenos para a idade gestacional provenientes de um hospital universitário na região sul do Brasil, acompanhados durante seis meses e comparados com dados de literatura a respeito de recém-nascidos adequados para a idade gestacional. Foram analisados dados antropométricos, características epidemiológicas e a evolução do exame neurológico e do desenvolvimento neuropsicomotor. Houve variações significativas na aquisição de habilidades como o sustento cefálico aos 3 meses e atraso na lalação. Nos demais aspectos os bebês nascidos pequenos para a idade gestacional evoluíram de forma semelhante aos padrões de lactentes normais. Sugere-se que estudos caso-controle sejam realizados com a finalidade de aprofundar a análise desses resultados.

Chronic low dose risperidone and clozapine alleviate positive but not negative symptoms in the rat neonatal ventral hippocampal lesion model of schizophrenia.

RATIONALE: The rat neonatal ventral hippocampal (VH) ibotenic lesion model has been proposed as a developmental model of schizophrenia, based on evidence that it encompasses aspects of the disorder including psychomotor agitation (hyperactivity), deficits in prepulse inhibition (PPI), and deficits in social interaction (SI), measures presumed to reflect positive symptoms, sensory gating deficits and negative symptoms, respectively. However, validation of the model as a predictive pharmacological screening tool has been minimal. OBJECTIVE: Determine the effects of a chronic 3-week low dose treatment of clozapine or risperidone on locomotor hyperactivity, PPI and SI in lesioned and control rats. RESULTS: Both clozapine, 2.5 mg/kg per day IP and risperidone, 0.1 mg/kg per day IP, reversed lesion-induced locomotor hyperactivity; however, the compounds also decreased locomotor activity in the non-lesioned controls. Clozapine 2.5 mg/kg per day and risperidone 0.1 mg/kg per day significantly attenuated lesion-induced PPI deficits. Neither compound induced a significant attenuation of lesion-induced SI deficits. In order to see if SI deficits required a higher dose of an antipsychotic, the dose of clozapine was increased to 4 mg/kg per day; however this dose induced such marked decreases in the activity and startle responses in the control rats, i.e. up to 74% decrease, that the effects on the lesioned rats could not be adequately interpreted. CONCLUSIONS: These data add further support to the neonatal VH lesion model as a predictive pharmacological screening assay for identifying compounds effective in the treatment of positive symptoms of schizophrenia. However, the usefulness of the model in detecting compounds effective in treating negative symptoms of schizophrenia is still in question.

Effects of selective dopamine D1 or D2 receptor blockade within nucleus accumbens subregions on ingestive behavior and associated motor activity.

Two anatomically and neurochemically distinguishable regions of the nucleus accumbens (Acb), the core and the shell, have been shown to differentially regulate feeding behavior. Nevertheless, despite the well-known role of Acb dopamine in the modulation of motivated behaviors, there have been no studies directly comparing the effects of acute dopamine receptor blockade in the Acb core versus the Acb shell on feeding. In this study, D1- or D2-selective dopamine receptor antagonists were infused bilaterally into the Acb core or shell of hungry rats, whereupon feeding, drinking, and spontaneous motor activity were monitored. Both the D1 antagonist SCH 23390 (0, 1, and 2 microg/0.5 microl) and the D2 antagonist raclopride (0, 1, and 2 microg/0.5 microl) markedly suppressed ambulation and rearing when infused into either the Acb core or shell. Total food intake and latency to begin feeding were unaffected by either drug in either site. SCH 23390 in the Acb shell, and raclopride in the Acb core or shell, significantly decreased the total number of feeding bouts. In the Acb core, raclopride produced a small but statistically significant increase in overall feeding duration. Dopamine receptor blockade in either site tended to increase mean feeding bout duration. Measures of drinking behavior were generally unaffected. Hence, dopamine receptor blockade in either the Acb core or shell of hungry rats suppressed spontaneous motor activity and shifted the structure of feeding towards longer bout durations, but did not alter the total amount of food consumed. In the Acb shell, the effects of D1 receptor blockade tended to be of greater magnitude than the effects of D2 receptor blockade, although major differences between core and shell effects were not observed. These results are discussed with regard to current theories of dopaminergic control of feeding behavior, and with reference to the functional heterogeneity of Acb subregions.