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Repeated pretreatment of morphine prevents morphine-induced amnesia: A possible involvement for dorsal hippocampal NMDA receptors.
Arch Iran Med. 2011 Jan; 14(1):32-8.AI

Abstract

BACKGROUND

Learning and memory processes can be affected by morphine administration. It has been previously demonstrated that the effects of morphine depend on the timing of drug administration. In the present study, the effects of microinjections of a NMDA receptor agonist and antagonist into the CA1 regions of the dorsal hippocampi (intra-CA1) on repeated pretreatment of morphine-induced prevention of morphine-induced amnesia have been investigated.

METHODS

Step-through inhibitory avoidance task of memory has been used to examine retrieval of memory formation, 24 h after training in male Wistar rats.

RESULTS

The results indicate that post-training administration of morphine (7.5 mg/kg) impaired memory retrieval, but not in the animals, which received previous repeated morphine (7.5 and 10 mg/kg) injections followed by morphine withdrawal. Repeated co-administration of NMDA (7.5 and 10 ng/rat, intra-CA1) with an ineffective dose of morphine (5 mg/kg), once daily for three days reversed morphine-induced amnesia. Repeated bilateral intra-CA1 microinjections of NMDA, once daily for three days followed by a five-day washout had no effect on the expression of amnesia produced by post-training morphine. Three-day administration of the NMDA receptor antagonist, D-AP5 (0.5 - 2 µg/rat, intra-CA1) followed by a five-day washout had no effect on morphine-induced amnesia. On the other hand, intra-CA1 microinjections of the same doses of D-AP5 prior to injection of 7.5 mg/kg of morphine (per day×3 days) decreased the reversal of morphine-induced amnesia.

CONCLUSION

These data imply that the dorsal hippocampal NMDA receptor mechanism(s) may modulate the effect-induced by repeated morphine administration on a challenge dose of morphine-induced amnesia.

Authors+Show Affiliations

Department of Pharmacology, Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Iran. Iran.zarinmr@ams.ac.irNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21194259

Citation

Zarrindast, Mohammad Reza, et al. "Repeated Pretreatment of Morphine Prevents Morphine-induced Amnesia: a Possible Involvement for Dorsal Hippocampal NMDA Receptors." Archives of Iranian Medicine, vol. 14, no. 1, 2011, pp. 32-8.
Zarrindast MR, Asadi F, Rezayof A. Repeated pretreatment of morphine prevents morphine-induced amnesia: A possible involvement for dorsal hippocampal NMDA receptors. Arch Iran Med. 2011;14(1):32-8.
Zarrindast, M. R., Asadi, F., & Rezayof, A. (2011). Repeated pretreatment of morphine prevents morphine-induced amnesia: A possible involvement for dorsal hippocampal NMDA receptors. Archives of Iranian Medicine, 14(1), 32-8. https://doi.org/011141/AIM.008
Zarrindast MR, Asadi F, Rezayof A. Repeated Pretreatment of Morphine Prevents Morphine-induced Amnesia: a Possible Involvement for Dorsal Hippocampal NMDA Receptors. Arch Iran Med. 2011;14(1):32-8. PubMed PMID: 21194259.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Repeated pretreatment of morphine prevents morphine-induced amnesia: A possible involvement for dorsal hippocampal NMDA receptors. AU - Zarrindast,Mohammad Reza, AU - Asadi,Fereshteh, AU - Rezayof,Ameneh, PY - 2011/1/4/entrez PY - 2011/1/5/pubmed PY - 2011/5/19/medline SP - 32 EP - 8 JF - Archives of Iranian medicine JO - Arch Iran Med VL - 14 IS - 1 N2 - BACKGROUND: Learning and memory processes can be affected by morphine administration. It has been previously demonstrated that the effects of morphine depend on the timing of drug administration. In the present study, the effects of microinjections of a NMDA receptor agonist and antagonist into the CA1 regions of the dorsal hippocampi (intra-CA1) on repeated pretreatment of morphine-induced prevention of morphine-induced amnesia have been investigated. METHODS: Step-through inhibitory avoidance task of memory has been used to examine retrieval of memory formation, 24 h after training in male Wistar rats. RESULTS: The results indicate that post-training administration of morphine (7.5 mg/kg) impaired memory retrieval, but not in the animals, which received previous repeated morphine (7.5 and 10 mg/kg) injections followed by morphine withdrawal. Repeated co-administration of NMDA (7.5 and 10 ng/rat, intra-CA1) with an ineffective dose of morphine (5 mg/kg), once daily for three days reversed morphine-induced amnesia. Repeated bilateral intra-CA1 microinjections of NMDA, once daily for three days followed by a five-day washout had no effect on the expression of amnesia produced by post-training morphine. Three-day administration of the NMDA receptor antagonist, D-AP5 (0.5 - 2 µg/rat, intra-CA1) followed by a five-day washout had no effect on morphine-induced amnesia. On the other hand, intra-CA1 microinjections of the same doses of D-AP5 prior to injection of 7.5 mg/kg of morphine (per day×3 days) decreased the reversal of morphine-induced amnesia. CONCLUSION: These data imply that the dorsal hippocampal NMDA receptor mechanism(s) may modulate the effect-induced by repeated morphine administration on a challenge dose of morphine-induced amnesia. SN - 1735-3947 UR - https://www.unboundmedicine.com/medline/citation/21194259/Repeated_pretreatment_of_morphine_prevents_morphine_induced_amnesia:_A_possible_involvement_for_dorsal_hippocampal_NMDA_receptors_ L2 - http://www.ams.ac.ir/AIM/NEWPUB/11/14/1/008.pdf DB - PRIME DP - Unbound Medicine ER -