Abstract: A method for treating conditions or diseases associated with deleterious vasoconstriction of the small arteries and arterioles of one or more organs or parts of a patient's body. In one embodiment, the method comprises administering a therapeutically effective amount of an antagonist to the &agr;2C-adrenergic receptor (&agr;2C-AR) to a patient with Raynaud's Phenomenon. Such method is used to ameliorate the cold-induced or stress-induced vasoreactive response that is associated with Raynaud's Phenomenon. The &agr;2C-AR antagonist is administered to the subject either prior to or after exposure of the patient to the cold or to stressIn another embodiment, the method is used to reduce the extent of deleterious vasoconstriction that occurs in the small arteries, arterioles, and microcirculation of the lungs, heart, kidneys, skin, or gastrointestinal tract of a patient, particularly a scleroderma patient.