PT  - JOURNAL ARTICLE
AU  - HELEN TREDWAY GRAHAM
TI  - THE NARCOSIS OF MUSCLE BY GASES
DP  - 1929 Sep 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 9--33
VI  - 37
IP  - 1
4099  - http://jpet.aspetjournals.org/content/37/1/9.short
4100  - http://jpet.aspetjournals.org/content/37/1/9.full
SO  - J Pharmacol Exp Ther1929 Sep 01; 37
AB  - 1. The narcotic gases, nitrous oxide, ethylene and acetylene, affect the contraction of isolated muscle exactly as ether vapor affects it, but at much higher tensions. 2. The threshold of muscular contraction in response to break shocks at first rises very slowly with suitable tensions of any of the narcotics, then goes up rapidly to 100 or more times its original value, and then again rises more slowly. The rapid and marked threshold-rise is designated as "narcosis." 3. With isolated frog sartorius, the range from 0 to 100 per cent cases of narcosis within thirty minutes, is covered by 0.04 to 0.08 atmosphere of ether vapor; by 1.67 to 3 atmospheres of acetylene; by 2.67 to 4 (?) atmospheres of ethylene; and by 3.00 to 4.33 atmospheres of nitrous oxide. The upper limit of these ranges is in each case 3 to 5 times the tension usually considered necessary for mammalian anesthesia. These data were obtained at various times in the months from May to December; in January the range for nitrous oxide was found to be 5 to 6 atmospheres. 4. Subnarcotic tensions produce relatively insignificant changes in the threshold. 5. The responses given by the muscles in narcosis are slight and slow, and are more or less localized under the stimulating electrode. They cannot be abolished by increasing the tension of the narcotic, but with sufficiently strong shocks persist up to the point where the muscle is irreversibly injured, as shown by failure to recover, or by permanent shortening (rigor). 6. Application of nitrogen at tensions (at least up to 10 atmospheres) far higher than the required tensions of the narcotic gases, has relatively little effect on the threshold of the muscle. 7. Increasing the oxygen tension to five times its normal value does not change the limiting narcotic tension of nitrous oxide. 8. The gases cannot be separated from other narcotics on the basis of any different action on anaerobic processes; nor can muscle be distinguished from nerve because of its supposed resistance to narcosis by gases.