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

Abstract

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.

• Authors: Raquele Kipper Mariani, Carlos Fernando Mello, Michelle Melgarejo Rosa, Ana Paula Chiapinotto Ceretta, Keli Camera, Maribel Antonello Rubin
• Journal: Psychopharmacology (Psychopharmacology (Berl)) Vol. 215 Issue 3 Pg. 483-91 (Jun 2011) ISSN: 1432-2072 [Electronic] Germany
• PMID: 21360010 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Analgesics, Opioid
• Biguanides
• Narcotic Antagonists
• Naloxone
• arcaine
• Morphine

Topics

• Analgesics, Opioid (administration & dosage, pharmacology)
• Animals
• Avoidance Learning (drug effects)
• Biguanides (administration & dosage, pharmacology)
• Dose-Response Relationship, Drug
• Injections, Intraperitoneal
• Male
• Memory (drug effects)
• Morphine (administration & dosage, pharmacology)
• Naloxone (administration & dosage, pharmacology)
• Narcotic Antagonists (administration & dosage, pharmacology)
• Rats
• Rats, Wistar