Susanna Ellis

Long-term effects of pre-pubertal fluoxetine on behaviour and monoaminergic stress response in stress-sensitive rats.

Objective Although prescription rates of antidepressants for children and adolescents have increased, concerns have been raised regarding effects on neurodevelopment and long-term outcome. Using a genetic animal model of depression, this study investigated the long-term effects of pre-pubertal administration of fluoxetine (FLX) on depressive-like behaviour in early adulthood, as well as on central monoaminergic response to an acute stressor. We postulated that pre-pubertal FLX will have lasting effects on animal behaviour and monoaminergic stress responses in early adulthood. Methods Flinders sensitive line (FSL) rats received 10 mg/kg/day FLX subcutaneously from postnatal day 21 (PnD21) to PnD34 (pre-pubertal). Thereafter, following normal housing, rats were either subjected to locomotor testing and the forced swim test (FST) on PnD60 (early adulthood), or underwent surgery for microdialysis, followed on PnD60 by exposure to acute swim stress and measurement of stressor-induced changes in plasma corticosterone and pre-frontal cortical monoamine concentrations. Results Pre-pubertal FLX did not induce a late emergent effect on immobility in FSL rats on PnD60, whereas locomotor activity was significantly decreased. Acute swim stress on PnD60 significantly increased plasma corticosterone levels, and increased pre-frontal cortical norepinephrine (NE) and 5-hydroxyindole-3-acetic acid (5-HIAA) concentrations. Pre-pubertal FLX significantly blunted the pre-frontal cortical NE and 5-HIAA response following swim stress on PnD60. Baseline dopamine levels were significantly enhanced by pre-pubertal FLX, but no further changes were induced by swim stress. Conclusion Pre-pubertal FLX did not have lasting antidepressant-like behavioural effects in genetically susceptible, stress-sensitive FSL rats. However, such treatment reduced locomotor activity, abrogated noradrenergic and serotonergic stressor responses and elevated dopaminergic baseline levels in adulthood.

Developing a Basic Mathematics Questionnaire for Grades 4 to 7

In this article, the authors report on the development of a basic mathematics questionnaire for Grades 4 to 7 (the BM(P)). The provisional instrument was completed by 1,103 Afrikaans-, English-and Tswana-speaking learners in Grades 4 to 7 in the North-West Province of South Africa. First-order factor analysis was carried out, item analysis was done, reliability coefficients and discrimination values were calculated, and norm tables were established. Weighted means were used to ensure that the results were proportional to the ratios of the language groups in the province. We (the authors) concluded that standardisation of the BM(P) yielded satisfactory results with regard to the determination of issues such as construct validity, reliability, validity and intercorrelations for Grade 4 to 7 learners in the North-West Province of South Africa.