Improvement of contextual memory by S 24795 in aged mice: comparison with memantine.
RESULTS
In comparison with 5-month-old mice, 18- to 19-month-old mice exhibited a severe and specific memory impairment in a contextual serial discrimination (CSD) task involving the learning and remembering of two successive spatial discriminations carried out on two distinct floors. This impairment was specific, as spatial memory, simultaneously tested on a simple discrimination (SD) task, was not affected in these aged mice. This deficit was completely reversed by 9-day per os administration of S 24795, a partial agonist of alpha 7 nicotinic receptors, at either 0.3 or 1.0 mg/kg. Memantine, an NMDA receptor antagonist, also had a memory-enhancing effect at a dose of 3.0 mg/kg, but not at 0.3 mg/kg.


CONCLUSIONS
The memory-enhancing effect of S 24795 was due to a strong enhancement of contextual memory as indicated by a decrease in interference rate, whereas memantine enhanced spatial/semantic memory. S 24795 was more effective than memantine and also appears to be more specific to flexible forms of memory, one of the first cognitive domains (i.e. episodic memory) affected in Alzheimer's disease.
Beracochea
Daniel
D
Centre de Neurosciences Intégratives et Cognitives, CNRS UMR 5228, Universités de Bordeaux 1 et 2, Avenue des Facultés, 33405 Talence-Cédex, France. d.beracochea@cnic.u-bordeaux1.fr
Boucard
Aurelie
A
Trocme-Thibierge
Caryn
C
Morain
Philippe
P
D000375:Aging; D000818:Animals; D004193:Discrimination Learning / Q000187:drug effects; D008297:Male; D008559:Memantine / Q000008:administration & dosage / Q000494:pharmacology*; D008568:Memory / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D018722:Nicotinic Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D011726:Pyridinium Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D011978:Receptors, Nicotinic / Q000502:physiology; D012691:Serial Learning / Q000187:drug effects; D064569:alpha7 Nicotinic Acetylcholine Receptor
C579166:Chrna7 protein, mouse; D018722:Nicotinic Agonists; D011726:Pyridinium Compounds; D016194:Receptors, N-Methyl-D-Aspartate; D011978:Receptors, Nicotinic; C524163:S 24795; D064569:alpha7 Nicotinic Acetylcholine Receptor; D008559:Memantine