Journal of Applied Physiology, Vol 56, Issue 4 891-895, Copyright © 1984 by American Physiological Society
Effects of pyridostigmine on ability of rats to work in the heat
R. Francesconi, R. Hubbard and M. Mager
Adult, male rats (300-325 g) were treated with pyridostigmine bromide (n =
22) or saline (n = 22) to quantitate the effects of cholinesterase
inhibition (64%) on the ability to work (9.14 m/min, level treadmill) in
the heat (35 degrees C). Pyridostigmine-treated rats had a mean endurance
of 23 min, whereas saline-treated animals ran for nearly 35 min (P less
than 0.001). Rates of rectal and skin temperature increments were
significantly higher (P less than 0.001) in pyridostigmine-treated rats as
were water losses (P less than 0.001). Exercise in the heat to hyperthermic
exhaustion effected anticipated increments in circulating urea nitrogen,
creatinine, lactate dehydrogenase, and potassium levels, whereas
pyridostigmine pretreatment had additive effects on lactate and creatine
kinase concentrations. Additionally, pyridostigmine elicited a significant
(P less than 0.01) hyperglycemia before exercise, an effect noted also with
other organophosphate simulants. We concluded that pyridostigmine-induced
cholinesterase inhibition had a variety of debilitating effects during work
in the heat.
