The iris inner smaller circle-circumference changes size when constricting or dilating. Edinger-Westphal nucleus reacts to taste stimuli by dilating and constricting the pupils. Blood vessel dilating medications such as iloprost may prevent blood vessel blockage. The most common surgical technique involves dilating the cervix and using a suction device. Cilostazol is a phosphodiesterase 3 inhibitor which works by inhibiting platelet aggregation and dilating arteries. The subject's pupils are dilated using a dilating agent to minimize fluctuations from accommodation. A pelvic exam may be done to see if the mother's cervix is dilating. Bloody show is another indication that the cervix is dilating. Combination with beta-adrenergic agonists increases the dilating effect on the bronchi. A dilating device may be passed over the guidewire to expand the tract. ISDN is in the nitrate family of medications and works by dilating blood vessels. Most treatments involve dilating major airways to improve shortness of breath among other symptoms. For instance, the tops to dilating drops are a different color than anti-allergy drops.