PMID- 23171436
OWN - NLM
STAT- MEDLINE
DCOM- 20150713
LR  - 20211021
IS  - 1476-5381 (Electronic)
IS  - 0007-1188 (Print)
IS  - 0007-1188 (Linking)
VI  - 168
IP  - 8
DP  - 2013 Apr
TI  - Dual effect of morphine in long-term social memory in rat.
PG  - 1786-93
LID - 10.1111/bph.12060 [doi]
AB  - BACKGROUND AND PURPOSE: Bimodal dose-response relationships have been 
      demonstrated in animals and humans following morphine administration. We examined 
      if systemic administration of morphine, in extremely low (mug) and high (mg, 
      analgesic) doses, changed the learning process. EXPERIMENTAL APPROACH: In the 
      social learning test, an adult rat investigates a juvenile. The juvenile is 
      submitted to a second encounter after a few days and investigation by the adult 
      should be reduced. Morphine was administered before the first encounter between 
      rats, and the critical test was performed 24, 72 or 168 h later, when animals 
      were re-exposed to each other, in the absence of morphine. KEY RESULTS: Low doses 
      of morphine, comparable with endogenous brain concentrations, enhanced long-term 
      memory recognition; while high doses did the reverse, indicating the adult failed 
      to recognize the juvenile. Recognition of a familiar rat appeared to be mediated 
      within the brain accessory olfactory bulb (AOB) by an opioid system intrinsic to 
      the olfactory system through mu-opioid receptors (MORs). At this supraspinal site, 
      the PLC/PKC signalling pathway was activated by extremely low morphine doses. 
      CONCLUSIONS AND IMPLICATIONS: Morphine treatment administration may either 
      disrupt or facilitate social memory, depending on the dose, extending to memory 
      formation the bimodal effects of morphine previously shown in pain. Social memory 
      formation elicited by extremely low morphine doses, was mediated within the AOB 
      by an opioid system, intrinsic to the olfactory system through MORs.
CI  - (c) 2012 The Authors. British Journal of Pharmacology (c) 2012 The British 
      Pharmacological Society.
FAU - Bianchi, Enrica
AU  - Bianchi E
AD  - Department of Medical Surgical Sciences and Neuroscience, University of Siena, 
      Siena, Italy. enrica.bianchi@unisi.it
FAU - Menicacci, Cristina
AU  - Menicacci C
FAU - Ghelardini, Carla
AU  - Ghelardini C
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Br J Pharmacol
JT  - British journal of pharmacology
JID - 7502536
RN  - 0 (Analgesics, Opioid)
RN  - 0 (Receptors, Opioid, mu)
RN  - 76I7G6D29C (Morphine)
SB  - IM
MH  - Analgesics, Opioid/*administration & dosage
MH  - Animals
MH  - Dose-Response Relationship, Drug
MH  - Memory, Long-Term/*drug effects
MH  - Morphine/*administration & dosage
MH  - Olfactory Bulb/metabolism
MH  - Rats
MH  - Receptors, Opioid, mu/metabolism
MH  - Signal Transduction/drug effects
PMC - PMC3623050
EDAT- 2012/11/23 06:00
MHDA- 2015/07/15 06:00
PMCR- 2014/04/01
CRDT- 2012/11/23 06:00
PHST- 2012/02/14 00:00 [received]
PHST- 2012/10/02 00:00 [revised]
PHST- 2012/10/21 00:00 [accepted]
PHST- 2012/11/23 06:00 [entrez]
PHST- 2012/11/23 06:00 [pubmed]
PHST- 2015/07/15 06:00 [medline]
PHST- 2014/04/01 00:00 [pmc-release]
AID - 10.1111/bph.12060 [doi]
PST - ppublish
SO  - Br J Pharmacol. 2013 Apr;168(8):1786-93. doi: 10.1111/bph.12060.