Hypobaric hypoxia-induced dendritic atrophy of hippocampal neurons is associated with cognitive impairment in adult rats

Titus, A. D. J. ; Shankaranarayana Rao, B. S. ; Harsha, H. N. ; Ramkumar, K. ; Srikumar, B. N. ; Singh, S. B. ; Chattarji, S. ; Raju, T. R. (2007) Hypobaric hypoxia-induced dendritic atrophy of hippocampal neurons is associated with cognitive impairment in adult rats Neuroscience, 145 (1). pp. 265-278. ISSN 0306-4522

Full text not available from this repository.

Official URL: http://linkinghub.elsevier.com/retrieve/pii/s0306-...

Related URL: http://dx.doi.org/10.1016/j.neuroscience.2006.11.037

Abstract

Simulated hypobaric hypoxia (HBH), resembling high altitude hypoxia severely affects the CNS and results in several physiological changes. The hippocampus is closely associated with learning and memory and an insult to this region affects cognition. Previous studies suggest that rapid or prolonged exposures to HBH are associated with psychomotor and cognitive impairments. The defense personnel, mountain climbers and rescue teams are exposed to such harsh environment and thus it demands a systematic study emphasizing the subtle effects of such extreme environments on cognitive function. Accordingly, this study evaluated the effect of hypobaric hypoxia on structural changes in the principal neurons of the hippocampus and learning in eight-arm radial maze. Adult male Wistar rats, subjected to simulated hypobaric hypoxia equivalent to an altitude of 6000 m for a period of 2 or 7 days, in a hypoxic chamber served as hypoxic group (HY). Rats housed in a similar chamber for the same period of time, without hypoxic exposure served as sham control (SC), while normal control (NC) group of rats were housed in standard laboratory conditions. The dendritic morphology of neurons in cornu ammonis region 1 (CA1) and cornu ammonis region 3 (CA3) was studied in Golgi-impregnated hippocampal sections. Exposure for 2 days to hypobaric hypoxia had minimal deleterious effects on the CA1 pyramidal neurons, while exposure for 7 days resulted in a significant decrease in the number of branching points, intersections and dendritic length. Unlike the CA1 pyramidal neurons, the CA3 neurons exhibited dendritic atrophy following both 2 and 7 days of hypoxic exposure. Further, hippocampal-dependent spatial learning was affected marginally following 2 day exposure, while 7 day exposure severely affected learning of the partially baited radial arm maze task. Our study suggests that dendritic atrophy in the hippocampus on exposure to HBH could be one of the bases for the cognitive deficits exhibited under such conditions.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:High Altitude Hypoxia; Golgi-impregnation; Radial Arm Maze; Neuronal Plasticity; Cognitive Deficits; Spatial Learning
ID Code:38498
Deposited On:30 Apr 2011 09:28
Last Modified:30 Apr 2011 09:28

Repository Staff Only: item control page