BetaCCM but not physostigmine enhancement of memory retrieval depends on emotional processes in mice.
BACKGROUND
The effects of methyl beta-carboline-3-carboxylate (betaCCM, an inverse agonists of GABA/benzodiazepine receptors) or physostigmine (a cholinesterase inhibitor) on retrieval processes and relationships with anxiety have been only marginally studied.


OBJECTIVE
This study investigates in mice the effects of acute betaCCM or physostigmine injections on retrieval of previously acquired discriminations involving distinct contextual cues (serial contextual discrimination; SCD) in a four-hole-board. Animals submitted to SCD were also evaluated for emotional reactivity in an elevated-plus maze.


METHODS
Mice were injected before the learning session began with a saline solution. Twenty-four hours later, mice were replaced on the context of the initial acquisition and a single dose of saline or betaCCM (0.5 or 1.5 mg/kg) or physostigmine (0.05 and 1.0 mg/kg) was injected 20 min before testing.


RESULTS
The highest dose of either betaCCM or physostigmine improved performance of the first discrimination in the SCD task. The higher dose of betaCCM produced anxiety-like reactivity in the plus maze, and scores of "anxiety" were significantly correlated with memory scores; in contrast, memory performance of physostigmine-treated subjects were totally independent of emotional reactivity.


CONCLUSIONS
These results show that, as opposed to physostigmine, betaCCM acts on retrieval processes specifically through its emotional component.
Beracochea
Daniel
D
Laboratoire de Neurosciences Cognitives, UMR CNRS 5106, Batiment Biologie Animale, Université de Bordeaux 1, Avenue des Facultés, 33405 Talence, France. d.beracochea@lnc.u-bordeaux1.fr
Celerier
Aurelie
A
Pierard
Christophe
C
D000818:Animals; D001007:Anxiety; D002243:Carbolines / Q000008:administration & dosage / Q000493:pharmacokinetics*; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D004644:Emotions / Q000187:drug effects / Q000502:physiology*; D005239:Fear / Q000187:drug effects / Q000502:physiology; D007274:Injections, Intraperitoneal; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D011939:Mental Recall / Q000187:drug effects* / Q000502:physiology*; D008722:Methods; D051379:Mice; D008810:Mice, Inbred C57BL; D010830:Physostigmine / Q000008:administration & dosage* / Q000493:pharmacokinetics; D013028:Space Perception / Q000502:physiology; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
D002243:Carbolines; D010830:Physostigmine; C036150:beta-carboline-3-carboxylic acid methyl ester