The present invention includes polymorphisms in nucleic acids encoding the alpha-2A adrenergic receptor and expressed alpha-2A adrenergic receptor molecule. The invention also pertains to methods and molecules for detecting such polymorphisms and transgenic animals expressing alpha-2A adrenergic receptor molecules. The invention further pertains to the use of such molecules and methods in the diagnosis, prognosis, and treatment of diseases such as cardiovascular and central nervous system diseases.