Effects of the dopamine D3 receptor agonist, R(+)-7-hydroxy-N,N-di-n-propyl-2-aminotetralin, on memory processes in mice.
The putative dopamine D3 receptor agonist, R(+)-7-hydroxy-N,N-di-n-propyl-2-aminotetralin (R(+)-7-OH-DPAT) (0.1-100 microg/kg, s.c.), administered before training, immediately after training, and before retention significantly shortened step-down latency of passive avoidance learning, indicating the amnesic effects of R(+)-7-OH-DPAT. Neither the dopamine D1 receptor antagonist, R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzaz epine maleate R(+)-SCH23390) (2.5 and 5 microg/kg, i.p.), nor the dopamine D2 receptor antagonist, S(-)-sulpiride (10 and 30 mg/kg, i.p.), markedly influenced the R(+)-7-OH-DPAT (10 and 100 microg/kg, s.c.)-induced amnesia. In addition, only a 1000 microg/kg dose of R(+)-7-OH-DPAT decreased locomotor activity; 1 and 100 microg/kg doses of the drug were ineffective. These results suggest that the amnesic effects of the dopamine D3 receptor agonist, R(+)-7-OH-DPAT, are not mediated via dopamine D1 or D2 receptors in the brain.
Ukai
M
M
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Meijo University, Nagoya, Japan. ukai@meijo-u.ac.jp
Tanaka
T
T
Kameyama
T
T
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D002316:Cardiotonic Agents / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D017448:Receptors, Dopamine D2 / Q000819:agonists*; D050637:Receptors, Dopamine D3; D013764:Tetrahydronaphthalenes / Q000494:pharmacology*
D002316:Cardiotonic Agents; D018491:Dopamine Agonists; C493594:Drd3 protein, mouse; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D013764:Tetrahydronaphthalenes; C031349:7-hydroxy-2-N,N-dipropylaminotetralin