PHYSIOLOGICAL EFFECTS OF THE NOBLE GASES ON FROG SCIATIC NERVE AND GASTROCNEMIUS MUSLCE.

Abstract

Evidence has been obtained which indicates that pressures up to 200 psi (gauge pressure) of helium, neon, nitrogen, or argon have no adverse effects on the ability of frog gastrocnemius muscles to produce tension when stimulated either directly or indirectly via the nerve. These gas tensions were without effect on nerve threshold and ability of nerve to conduct impulses. Experiments revealed that high tensions of gases do not result in fatiguing muscle at a faster rate than at 1 atm air. Krypton may have had a slight inhibitory effect on muscle ability to produce tension. Xenon or nitrous oxide, 100 psi, exerted a profound inhibitory effect on ability of gastrocnemius muscles to produce tension. These two gases appeared to have primarily a direct effect on muscle. On isolated sciatic nerve preparations, it was found that 100 psi xenon or 80 psi nitrous oxide exerted a slight depressing effect on nerve excitability. As the Pxe or Pn2o increased, nerve excitability decreased at a more rapid rate. The decreased nerve excitability was completely reversible.