Effects of Dimethyl Sulfoxide (DMSO) on the Contraction of the Rat Iris Muscle

ABSTRACT

PURPOSE: To evaluate the effects of DMSO on the iris muscle contractility and to compare DMSO with other detergents(ethanol and triton-x 100). METHODS: After anesthesizing rats with an intraperitoneal injection of pentobarbital sodium, each animal was fixed under microscope. The pupil response to the drugs was examined by CCD camera and the video edge motion detector was used for measurement of alteration of the pupil size. The pupil response to the drugs was recorded by MacLab chart(version 3.6/s). RESULTS: Miosis induced by DMSO was initiated after 5 minutes, peaked at around 30 minutes and maintained until 3 hours after instillation. Miotic effect of DMSO was in a dose dependent manner ranging 0.01%-10% and was not reversed after washout. All detergents used in the present experiment induced miosis, however, DMSO elicited the strongest miotic response. After pretreatment with atropine, DMSO-induced miotic response was not affected, showing similar changes with control group. CONCLUSIONS: Taken together, it is concluded that DMSO induces miosis by inducing relaxation of iris dilator muscle.