Journal of Applied Physiology, Vol 70, Issue 2 497-503, Copyright © 1991 by American Physiological Society
Effect of exposure to high pressure on subsequent spatial learning and memory in rats
B. Wardley-Smith, C. Dore, J. Coleman, A. Cowey, M. J. Halsey and S. Hudson
Division of Anaesthesia, Clinical Research Centre, Harrow, Middlesex, United Kingdom.
The effects of high helium pressure on the subsequent acquisition of
spatial memory were studied in male rats. Thirty-two rats were exposed to
65 ATA helium-oxygen pressure for 4.2 days, decompressed (total time in
chamber 5 days), and then tested in an eight-arm radial maze. Thirty-two
control rats were exposed in the chamber to 1 ATA air. Each rat had 20
sessions in the maze (2 sessions/day for 10 days), and the number of
correct (visiting an arm not previously visited to obtain the reward
pellet) and incorrect choices (visiting a previously visited arm) were
recorded. Statistical analysis showed that the rats exposed to 65 ATA
performed significantly better than 1-ATA controls during the first 8 of 20
sessions. This effect was most pronounced in sessions 5-8. Results for
sessions 9-20 showed that the pressure-treated rats still made more correct
choices but to an extent that did not always reach statistical
significance. Possible explanations include the pressure-treated rats
performing better because of hunger after a lower food consumption at
pressure. Alternatively, pressure itself may enhance proposed mechanisms of
spatial memory such as long-term potentiation.
