Cholinergic system, rearing environment and trajectory learning during aging in mice.
Three, 12- and 20-month-old C57BL6/J mice, reared in standard conditions or in enriched environments, were administered subcutaneously either scopolamine hydrobromide, 0.6 or 1.2 mg kg(-1), or physiological saline (control mice) 15 min before testing their abilities to find an invisible platform in a modified version of the Morris water maze, the starting point being kept unchanged throughout the experiment to allow the aged animals to solve the task. The results demonstrated that: 1) All control mice, whatever their age, were able to learn the platform location, but the number of trials needed to reach the learning criterion (3 consecutive trials in less than 8 s) increased with age; 2) All the scopolamine-treated mice, whatever their age, were also able to learn the platform location. However, compared to age-matched controls, the number of trials needed to reach the learning criterion was greater; 3) Rearing the animals in an enriched environment antagonized the effect of scopolamine, but only in the youngest (3 month-old) mice. All control and scopolamine-treated mice, whatever their age and their rearing environment, remembered, 7 days later, the platform location.
Thouvarecq
R
R
UPRES PSY.CO EA 1780, Faculté des Sciences, Laboratoire de Neurobiologie de l'Apprentissage, Université de Rouen, 76821 Mont-Saint-Aignan Cedex, France.
Caston
J
J
Protais
P
P
D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D004777:Environment; D004924:Escape Reaction / Q000187:drug effects / Q000502:physiology; D005260:Female; D006799:Housing, Animal; D008297:Male; D016555:Matched-Pair Analysis; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology*; D045442:Rotarod Performance Test; D012601:Scopolamine / Q000494:pharmacology*
D018727:Muscarinic Antagonists; D012601:Scopolamine