Journal of Applied Physiology, Vol 38, Issue 2 220-227, Copyright © 1975 by American Physiological Society
Rate factors in development of the high-pressure neurological syndrome
R. W. Brauer, R. W. Beaver, W. M. Mansfield, F. O'Connor and L. W. White 3rd
The effect of varying the pressure/time profile upon development of tremors
and convulsions of the high-pressure neurological syndrome was studied in
adult mice and squirrel monkeys and in baby mice. Two distinct response
patterns were observed. In the adults rapid compression produces early
onset of convulsions; convulsions subside rapidly when animals are held at
constant pressure just above the convulsion point; and interrupted
compression schedules show that total compression time rather than
instantaneous compression rate at the moment seizures develop is the
controlling parameter. Baby mice up to 12 days of age, by contrast, fail to
show any perceptible relation between compression rate and convulsion
threshold pressure (Pc); their seizures continue for a considerable period
of time after a constant pressure level just above the convulsion threshold
has been reached; and interrupted compressions of type a fail to change
their convulsion threshold. Together with supplementary data regarding
tremor thresholds and the transient increase of convulsion thresholds by
prior seizures these results lead to a proposed schema describing these
phenomena in terms of a pressure-dependent primary event predisposing to
tremors and convulsions; a time-dependent event counteracting the
convulsions (absent in baby mice); and a transient effect of prior
convulsions, raising subsequent Pc.
