title: New observations on pressure-induced motor disturbances in a small mammal.
abstract: New observations on pressure-induced motor disturbances in a small mammal. Undersea Biomed. Res. 4(1):1-8.-Adult and baby mice were subjected to helium pressures up to 120 atm. Pressure-induced changes in motor acitivity (tremors and convulsions) were monitored both visually and with a noninvasive mechanical transducer. A study of five rates of compression showed that adult convulsion pressure thresholds (Pc) fell from a maximum of 90 atm at 20 atm/hr to a minimum of 63 atm at 610 atm/hr, Pc for baby mice rose from 53 atm at 8 days to reach the adult value (85-90 atm) at 21 days of age. Measurements of accommodation, or the decline in motor disturbances at constant pressure, are described. Animals allowed to accommodate for five hours at a pressure 9% higher than the first Pc (85 atm) and then compressed further showed a significantly higher second Pc (114 atm) than animals allowed one hour to accommodate (100 atm). The effects on including nitrogen in the heliox compression mixture on accommodation are also described.
mesh_terms: D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001272:Atmosphere; D001274:Atmospheric Pressure; D005260:Female; D006371:Helium; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000502:physiology*; D009584:Nitrogen / Q000494:pharmacology; D010100:Oxygen; D012640:Seizures / Q000503:physiopathology; D013997:Time Factors; D014202:Tremor / Q000503:physiopathology
chemical_list: D006371:Helium; D009584:Nitrogen; D010100:Oxygen