Comparative effects of alpha-2 receptor agents and THA on the performance of adult and aged rats in the delayed non-matching to position task.
The present study investigated the effects of dexmedetomidine (an alpha-2 adrenoceptor agonist), atipamezole (an alpha-2 adrenoceptor antagonist) and tacrine (an inhibitor of acetylcholinesterase) on the performance of adult and aged rats in a delayed non-matching to position task assessing spatial short-term memory. Most of the aged rats were impaired in the pretraining phases and in the acquisition of the non-delayed version of the task. After a substantial training period of the delayed version of the task, both adult and aged rats reached their asymptotic level of performance. Both adult and aged rats showed a decline in the percent correct responses at the longest delays in this task, and a delay independent decrease in the percent correct responses across the delays (0-30 s) was found in the group of aged rats (25-month-old) as compared to the adults (10-month-old). Dexmedetomidine (0.3, 1.0 or 3.0 micrograms/kg), atipamezole (0.03, 0.3 or 3.0 mg/kg) and tacrine (1.0 or 3.0 mg/kg) did not increase the percent correct responses in adult or aged rats. The highest doses of dexmedetomidine and tacrine decreased behavioural activity of rats during this short-term memory testing. Atipamezole (0.03 mg/kg) increased behavioural activity of rats. The results suggest that acute, systemic administrations of alpha-2 drugs or an anticholinesterase do not improve short-term memory in rats.
Sirviö
J
J
Department of Neurology, University of Kuopio, Finland.
Harju
M
M
Riekkinen
P
P
Haapalinna
A
A
Riekkinen
P J
PJ
D058647:Adrenergic alpha-2 Receptor Agonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000375:Aging / Q000523:psychology*; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects*; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D020926:Medetomidine; D008570:Memory, Short-Term / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects*; D012055:Reinforcement Schedule; D013028:Space Perception / Q000187:drug effects; D013619:Tacrine / Q000494:pharmacology*
D058647:Adrenergic alpha-2 Receptor Agonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D007093:Imidazoles; D018341:Receptors, Adrenergic, alpha-2; C050701:atipamezole; D013619:Tacrine; D020926:Medetomidine