Effect of Induced Pain on Pain Threshold.

Abstract

Pain threshold detns. were made on a group of normal subjects when an alternating current was applied to a tooth through a metal filling. The voltage at which the subject first experienced a painful sensation was considered the threshold level. In the exptl. group, pain was produced by spraying ethylchloride to an area of one square inch over the anterior surface of the subject''s tibiae for a period of 20 secs. Pain thresholds were detd. before and at 30-min. intervals for 2 hrs. after the application of ethylchloride. In the control detns., the mean change in threshold value for the entire group was minus 0.003 volt; the corresponding value for the period following application of ethylchloride was plus 0.129 volt. The induced pain of short duration produced long lasting analgesic effects.