Animal models of neuropsychiatric disorders are current topics in behavioral neuroscience. Application of non-competitive antagonists of NMDA receptors (such as MK-801) was proposed as a model of schizophrenia, as it leads to specific behavioral alterations, which are partly analogous to human psychotic symptoms. This study examined an animal model of schizophrenia induced by a systemic application of MK-801 (0.15 and 0.20 mg/kg) into rats tested in the active allothetic place avoidance (AAPA) task. Previous studies suggested that MK-801 may interact in vivo with other neurotransmitter systems, including noradrenergic system. Our experiments therefore evaluated the hypothesis that both locomotor stimulation and deficit in avoidance behavior in AAPA task induced by this drug would be reversible by application of alpha1-adrenergic antagonist prazosin (1 and 2 mg/kg). The results showed that both doses of prazosin partia lly reversed hyperlocomotion induced by higher doses of MK-801 and an avoidance deficit measured as number of entrances into the shock sector. Interestingly, no effect of prazosin on the MK-801-induced decrease of maximum time between two entrances (another measure of cognitive performance) was observed. These results support previous data showing that prazosin can compensate for the hyperlocomotion induced by MK-801 and newly show that this partial reduction sustains even in the forced locomotor conditions, which are involved in the AAPA task. The study also shows that certain parameters of avoidance efficiency may be closely related to locomotor activity, whereas other measures of cognition may more selectively reflect cognitive changes., A. Stuchlík, T. Petrásek, K. Valeš., and Obsahuje seznam literatury
Schizophrenia is a devastating disorder affecting 1 % of the world's population. An important role in the study of this disease is played by animal models. Since there is evidence that acute psychotic episodes can have consequences on later cognitive functioning, the present study has investigated the effects of a single systemic application of higher doses of (+)MK-801 (3 mg/kg and 5 mg/kg) to adult male Long-Evans rats from the Institute’s breeding colony on delayed testing in the active place avoidance task with reversal on the Carousel (a rotating arena). Besides significant mortality due to the injections, a disruption of procedural functions in active place avoidance, after the dose 5 mg/kg was observed. It was concluded that Long-Evans rats from our breeding colony do not represent a suitable biomodel for studying the effects of single high-dose NMDA antagonists., V. Lobellová, E. Brichtová, T. Petrásek, K. Valeš, A. Stuchlík., and Obsahuje bibliografii
Spatial navigation comprises a widely-studied complex of animal behaviors. Its study offers many methodological advantages over other approaches, enabling assessment of a variety of experimental questions and the possibility to compare the results across different species. Spatial navigation in laboratory animals is often considered a model of higher human cognitive functions including declarative memory. Almost fifteen years ago, a novel dry-arena task for rodents was designed in our laboratory, originally named the place avoidance task, and later a modification of this approach was established and called active place avoidance task. It employs a continuously rotating arena, upon which animals are trained to avoid a stable sector defined according to room-frame coordina tes. This review describes the development of the place avoidance tasks, evaluates the cognitive processes associated with performance and explores the application of place avoidance in the testing of spatial learning after neuropharmacological, lesion and other experimental manipulations., A. Stuchlík ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Neurotransmitter substrate of spatial cognition belongs to current topics in behavioral neuroscience. The present study examined the effects of serotonin depletion with p-chlorophenylalanine on learning of rats in active place avoidance, a spatial task requiring allothetic mapping and cognitive coordination and highly dependent upon hippocampus. Serotonin depletion transiently increased locomotor activity in response to footshocks, but it did not change the avoidance efficiency measured by three spatial parameters. These results suggest that serotonin neurotransmission is not crucial for cognitive coordination and allothetic learning, i.e. the processes, which are crucial for active place avoidance performance., T. Petrásek, A. Stuchlík., and Obsahuje seznam literatury