Dysbarism: osmosis caused by dissolved gas?

The pressure in an osmometer, filled with nitrous oxide-saturated water separated from water by a polyurethane polyether membrane 2.5 microns in thickness, rose slowly by 8 to 20 millimeters (of water) in 10 minutes before gradually returning to close to zero within 2 hours. The permeation coefficient of the membrane was approximately 1000 times greater for water than for gases. The osmotic pressure of water saturated with nitrous oxide at 1 atmosphere, derived from the freezing point of the gas solution, was 1.5 atmospheres. It is concluded that dissolved gases exert osmotic pressure. Partial-pressure gradients of dissolved gases in the tissues of animals and man should cause flows of water along osmotic gradients, which may partially account for some of the symptoms and signs of dysbarism.

Hydraulic compression of mice to 166 atmospheres

Hydraulic uniform compression elicited tremors, uncoordinated limb movements, and tonic convulsions in liquid-breathing mice at pressures ranging from 50 to 100 atmospheres. Such abnormal muscular activity was observed neither in control animals nor in mice caudally to a spinal transection. Uniform compression of isolated preparations of mouse muscle in saline failed to contract at pressures up to 200 atmospheres.