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Physostigmine: dose-response effects on endurance and thermoregulation during exercise
C B Matthew1, R P Francesconi, R W Hubbard
1US Army Res. Inst. of Environmental Med., Natick, MA 01760-5007.
Life Sciences
|January 1, 1992
Summary
Physostigmine (PH) administration to exercising rats dose-dependently reduced endurance and impaired thermoregulation. These findings establish the exercising rat as a viable model for studying anticholinergic drug potency.
Area of Science:
- Exercise Physiology
- Pharmacology
- Neuroscience
Background:
- Previous studies indicated physostigmine (PH) impairs endurance and thermoregulation in exercising rats.
- Determining dose-response effects is crucial for validating the exercising rat model for anticholinergic drug potency assessment.
Purpose of the Study:
- To establish the dose-response relationship of physostigmine salicylate administration on endurance and thermoregulation in exercising rats.
- To validate the exercising rat model for evaluating the relative anticholinergic potency of drugs.
Main Methods:
- Rats (N=12/group) received saline, 50, 100, or 200 µg/kg physostigmine salicylate before treadmill exercise.
- Exercise parameters included a 6-degree incline at 11 m/min in 26°C and 50% relative humidity.
- Endurance (run time to exhaustion) and core body temperature changes were monitored.
Main Results:
- Physostigmine administration resulted in a dose-dependent decrease in running time and an increase in the rate of core temperature rise.
- 50, 100, and 200 µg/kg PH reduced run times to 80%, 64%, and 48% of control, respectively.
- Cholinergic symptoms (salivation, tremors, defecation) also increased with higher physostigmine doses.
Conclusions:
- Physostigmine exhibits dose-dependent effects on endurance, thermoregulation, and cholinergic symptoms in exercising rats.
- The exercising rat model is validated for assessing the relative potency of cholinergic therapies based on these dose-dependent responses.