Effect of naloxone and morphine on arcaine-induced state-dependent memory in rats.

Raquele Kipper Mariani, Carlos Fernando Mello, Michelle Melgarejo Rosa, Ana Paula Chiapinotto Ceretta, Keli Camera, Maribel Antonello Rubin

Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil.

Psychopharmacology 2011 Jun

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Arcaine is a competitive antagonist of the polyamine binding site at the N-methyl-D-aspartic acid receptor which induces state-dependent recall. However, no study has addressed the involvement of other neurotransmitter/neuromodulators in arcaine-induced state dependency. The current study investigates whether the opioid system is involved in arcaine-induced state-dependent memory retrieval of the inhibitory avoidance task (IA) in rats. The systemic administration of arcaine (30 mg/kg, intraperitoneally (i.p.)) or morphine (5 mg/kg, i.p.) 0, 3, 6, or 9 h post-training, reduced step-down latencies at testing. Arcaine (30 mg/kg, i.p.) or morphine (5 mg/kg, i.p.) injection 30 min before testing reversed the performance deficit induced by administration of arcaine or morphine 0, 3 or 6, but not 9 h post-training. The reversal of arcaine-induced impairment of IA performance was completely transferred to morphine and vice versa. The association of low and ineffective doses of morphine and arcaine (10 and 1.5 mg/kg, respectively) were additive and caused state dependency. Naloxone (2 mg/kg, 3 min post-training, or 1 mg/kg, 1 h pre-test, i.p.) reversed the amnesia and the state dependency induced by morphine and arcaine. These results suggest that state dependency induced by arcaine involves the opioid system.

Citation

Raquele Kipper Mariani, Carlos Fernando Mello, Michelle Melgarejo Rosa, Ana Paula Chiapinotto Ceretta, Keli Camera, Maribel Antonello Rubin. Effect of naloxone and morphine on arcaine-induced state-dependent memory in rats. Psychopharmacology. 2011 Jun;215(3):483-91