Björklund M, Sirviö J, Puoliväli J, Sallinen J, Jäkälä P, Scheinin M, Kobilka B K, Riekkinen P
Department of Neurology and Neuroscience, University of Kuopio, Kuopio, FIN-70211, Finland.
Mol Pharmacol. 1998 Sep;54(3):569-76. doi: 10.1124/mol.54.3.569.
Drugs acting via alpha2-adrenoceptors modulate cognitive functions mediated via frontostriatothalamic feedback loops. The alpha2C-adrenoceptor subtype is expressed in the basal ganglia, hippocampus, and neocortex, areas that are involved in memory and other cognitive functions. alpha2C-Overexpressing (OE) mice were impaired in spatial or nonspatial water maze (WM) tests, and alpha2 antagonist treatment fully reversed the WM escape defect in OE mice. However, alpha2C-overexpression did not influence open field and passive avoidance behaviors or cortical EEG arousal or the actions of alpha2 agonist or antagonist drugs on these functions. Our results suggest that alpha2C-adrenoceptors can modulate navigation to a hidden or visible escape platform, whereas many other actions of alpha2-adrenergic agents, such as sedation, are not mediated via alpha2C-adrenoceptors. Therefore, alpha2-agonists lacking alpha2C-AR affinity or alpha2C-AR subtype-selective alpha2 antagonists could modulate functioning of frontostriatothalamic feedback loops more effectively than the current subtype-nonselective drugs.
