title: The neurokinin-3 receptor agonist senktide facilitates the integration of memories for object, place and temporal order into episodic memory.
abstract: Senktide, a potent neurokinin-3 receptor (NK3-R) agonist, has been shown to have promnestic effects in adult and aged rodents and to facilitate episodic-like memory (ELM) in mice when administrated before the learning trial. In the present study we assessed the effects of senktide on memory consolidation by administering it post-trial (after the learning trial) in adult rats. We applied an ELM test, based on the integrated memory for object, place and temporal order, which we developed (Kart-Teke, de Souza Silva, Huston, & Dere, 2006). This test involves two learning trials and one test trial. We examined intervals of 1h and 23 h between the learning and test trials (experiment 1) in untreated animals and found that they exhibited intact ELM after a delay of 1 h, but not 23 h. In another test for ELM performed 7 days later, vehicle or senktide (0.2 mg/kg, s.c.) was applied immediately after the second learning trial and the test was conducted 23 h later (experiment 2). Senktide treatment recovered components of ELM (memory for place and object) compared with vehicle-treated animals. After one more week, vehicle or senktide (0.2 mg/kg, s.c.) was applied post-trial and the test conducted 6h later (experiment 3). The senktide-treated group exhibited intact ELM, unlike the vehicle-treated group. Finally, animals received post-trial treatment with either vehicle or SR142801, a selective NK3-R antagonist (6 mg/kg, i.p.), 1 min before senktide injection (0.2 mg/kg, s.c.) in the ELM paradigm and were tested 6h later (experiment 4). The vehicle+senktide group showed intact ELM, while the SR142801+senktide group did not. The results indicate that senktide facilitated the consolidation or the expression of ELM and that the senktide effect was NK3-R dependent.
authors: Center for Behavioral Neuroscience, Institute of Experimental Psychology, University of Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
authors: Owen Y
authors: OY
authors: Chao
authors: Clinic of Nuclear Medicine, University Hospital Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany.
authors: Susanne
authors: S
authors: Nikolaus
authors: Center for Behavioral Neuroscience, Institute of Experimental Psychology, University of Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany. Electronic address: jph@uni-duesseldorf.de.
authors: Joseph P
authors: JP
authors: Huston
authors: Center for Behavioral Neuroscience, Institute of Experimental Psychology, University of Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
authors: Maria A
authors: MA
authors: de Souza Silva
mesh_terms: D000818:Animals; D008568:Memory / Q000187:drug effects*; D061212:Memory, Episodic; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D018042:Receptors, Neurokinin-3 / Q000819:agonists*; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors
chemical_list: D010446:Peptide Fragments; D018042:Receptors, Neurokinin-3; C054724:senktide; D013373:Substance P
keywords: Episodic-like memory; NK3 receptors; Object recognition; Senktide