The effect of antagonism of adrenergic receptors on spatial learning in laboratory rats.

Spatial navigation is an important aspect of animal behavior, and is often regarded as a model of higher cognitive functions, e.g. declarative memory. It can be easily assessed by various behavioral tasks ("mazes"), and compared even across different species. Therefore, spatial tasks are especially suitable for evaluating potential psychoactive drugs in an animal model. This work deals mainly with noradrenergic neurotransmitter system and its influence on learning, memory and spatial behavior. The experimental part focuses on effects of subtype-specific noradrenergic antagonists prazosin, idazoxan and propranolol, and also a D2 dopaminergic antagonist, sulpiride, in Active Allothetic Place Avoidance (AAPA) task, a novel spatial task, well suited for measuring both cognitive and motor impairments. Rats with high doses of noradrenergic antagonists show combined impairment in both cognitive and motor aspect of the task. β-adrenergic antagonist propranolol also causes specific cognitive impairment in a lower dose of 25 mg/kg, but it fails to induce long-term memory impairment when given after experimental session. Co-application of alpha-1 adrenergic and D2 dopaminergic antagonists, prazosin and sulpiride, causes a severe motor and cognitive impairment, even at doses that do not influence animal behavior when..