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

• Published in: Psychopharmacologia 2011-06, Vol.215 (3), p.483-491
• Main Authors: Mariani, Raquele Kipper, Mello, Carlos Fernando, Rosa, Michelle Melgarejo, Ceretta, Ana Paula Chiapinotto, Camera, Keli, Rubin, Maribel Antonello
• Format: Article
• Language: English
• Subjects: Analgesics, Opioid - administration & dosage; Analgesics, Opioid - pharmacology; Animals; Aspartate; Avoidance Learning - drug effects; Biguanides - administration & dosage; Biguanides - pharmacology; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Dose-Response Relationship, Drug; Drug addiction; Injections, Intraperitoneal; Male; Medical sciences; Memory; Memory - drug effects; Methyl aspartate; Morphine; Morphine - administration & dosage; Morphine - pharmacology; Naloxone; Naloxone - administration & dosage; Naloxone - pharmacology; Narcotic Antagonists - administration & dosage; Narcotic Antagonists - pharmacology; Narcotics; Neurosciences; Neurotransmitters; Original Investigation; Pharmacology/Toxicology; Polyamines; Psychiatry; Psychopharmacology; Rats; Rats, Wistar; Rodents
• ISSN: 0033-3158; 1432-2072
• DOI: 10.1007/s00213-011-2215-6

Rationale 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. Objectives 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. Results 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. Conclusion These results suggest that state dependency induced by arcaine involves the opioid system.