A double dissociation within the hippocampus of dopamine D-1/D-5 receptor and beta-adrenergic receptor contributions to the persistence of long-term potentiation

We compared the effects of the D-1/D-5 receptor antagonist SCH-23390 with t he beta-adrenergic receptor antagonist propranolol on the persistence of lo ng-term potentiation in the CA1 and dentate gyrus subregions of the hippoca mpus. In slices, SCH-23390 but not propranolol reduced the persistence of l ongterm potentiation in area CA1 without affecting its induction. The drugs exerted reverse effects in the dentate gyrus, although in this case the in duction of long-term potentiation was also affected by propranolol. The lac k of effect of SCH-23390 on the induction and maintenance of long-term pote ntiation in the dentate gyrus was confirmed in awake animals. The drug also had little or no effect on the expression of inducible transcription facto rs. In area CA1 of awake animals, SCH-23390 blocked persistence of longterm potentiation beyond 3 h, confirming the results in slices. To rule our a d ifferential release of catecholamines induced by our stimulation protocols between brain areas, we compared the effects of the D-1/D-5 agonist SKF-383 93 with the beta-adrenergic agonist isoproterenol on the persistence of a w eakly induced, decremental long-term potentiation in CA1 slices. SKF-38393 but not isoproterenol promoted greater persistence of long-term potentiatio n over a 2-h period. In contrast, isoproterenol but not SKF-38392 facilitat ed the: induction of long-term potentiation. These data demonstrate that there is a double dissociation of the catechola mine modulation of long-term potentiation between CA1 and the dentate gyrus , suggesting that long-term potentiation in these brain areas may be differ entially consolidated according to the animal's behavioural state. (C) 1999 IBRO. published by Elsevier Science Ltd.