Photoactivation of Smooth Muscle with the Ruby Laser

摘要

Previous laser studies have indicated that a biologic effect is derived from the absorption of energy by a chromophore. Exceptions to this general rule, including the cessation of peristaltic movement in segments of chick intestine, have prompted a study of the response of smooth muscle systems to treatment with a ruby laser. Laser energy over a range of 100 to 1000 J/sq. cm was observed to stimulate contraction of smooth muscle from segments of salamander intestine and from excised rabbit iris sphincter muscle. The rapid contraction was observed to be confined to the tissue within the target diameter. Relaxation to its original state occurred within 1 to 4 minutes, depending upon the amplitude of the muscular excursion. Iris tissue containing pigment showed a response to a lower laser energy level, and the contractions showed a greater excursion than analogous tissue from an albino rabbit. The possibility of two-photon absorption by the nonpigmented muscle systems was discussed. (Author)