Altitude acclimatization improves submaximal cognitive performance in mice and involves an imbalance of the cholinergic system
Open Access
- 15 June 2013
- journal article
- Published by American Physiological Society in Journal of Applied Physiology
- Vol. 114 (12), 1705-1716
- https://doi.org/10.1152/japplphysiol.01298.2012
Abstract
The aim of this work was to reveal a hypothetical improvement of cognitive abilities in animals acclimatized to altitude and performing under ground level conditions, when looking at submaximal performance, once seen that it was not possible when looking at maximal scores. We modified contrasted cognitive tasks (object recognition, operant conditioning, eight-arm radial maze, and classical conditioning of the eyeblink reflex), increasing their complexity in an attempt to find performance differences in acclimatized animals vs. untrained controls. In addition, we studied, through immunohistochemical quantification, the expression of choline acetyltransferase and acetyl cholinesterase, enzymes involved in the synthesis and degradation of acetylcholine, in the septal area, piriform and visual cortexes, and the hippocampal CA1 area of animals submitted to acute hypobaric hypoxia, or acclimatized to this simulated altitude, to find a relationship between the cholinergic system and a cognitive improvement due to altitude acclimatization. Results showed subtle improvements of the cognitive capabilities of acclimatized animals in all of the tasks when performed under ground-level conditions (although not before 24 h), in the three tasks used to test explicit memory (object recognition, operant conditioning in the Skinner box, and eight-arm radial maze) and (from the first conditioning session) in the classical conditioning task used to evaluate implicit memory. An imbalance of choline acetyltransferase/acetyl cholinesterase expression was found in acclimatized animals, mainly 24 h after the acclimatization period. In conclusion, altitude acclimatization improves cognitive capabilities, in a process parallel to an imbalance of the cholinergic system.Keywords
This publication has 36 references indexed in Scilit:
- Role of cholinergic markers on memory function of rats exposed to hypobaric hypoxiaEuropean Journal of Pharmacology, 2011
- The cholinergic system in aging and neuronal degenerationBehavioural Brain Research, 2011
- Acetylcholinesterase inhibitors enhance cognitive functions in rats following hypobaric hypoxiaBehavioural Brain Research, 2009
- High altitude memory impairment is due to neuronal apoptosis in hippocampus, cortex and striatumJournal of Chemical Neuroanatomy, 2008
- Neonatal exposure to intermittent hypoxia enhances mice performance in water maze and 8-arm radial maze tasksJournal of Neurobiology, 2005
- Degree of inhibition of cortical acetylcholinesterase activity and cognitive effects by donepezil treatment in Alzheimer's diseaseJournal of Neurology, Neurosurgery & Psychiatry, 2005
- An in vitro and in vivo study of early deficits in associative learning in transgenic mice that over‐express a mutant form of human APP associated with Alzheimer's diseaseEuropean Journal of Neuroscience, 2004
- Elevation-Dependent Symptom, Mood, and Performance Changes Produced by Exposure to Hypobaric HypoxiaThe International Journal of Aviation Psychology, 1998
- Hypobaric hypoxia impairs spatial memory in an elevation-dependent fashionBehavioral and Neural Biology, 1994
- Enigmatic bipolar cell of rat visual cortexJournal of Comparative Neurology, 1988