Effect of compression rate on HPNS convulsion threshold in the euthermic rat.

The modification of the development of the high pressure nervous syndrome (HPNS) has been demonstrated by varying the external environment (chamber temperature, compression rate) or the internal environment (core temperature, pharmacology, age). This study examined the effects of compression rate on the convulsion-threshold pressure and EEG activity in 68 adult male Wistar rats with chronically implanted electrodes. Restrained animals were individually compressed at a predetermined rate in helium-oxygen to a simulated depth of 4500 fsw (137 ATA), with colonic temperature maintained at normal levels. Six compression rates showed that convulsion-threshold pressure for euthermic rats did not significantly differ between any of the groups.