Evaluation of the Role of the Autonomic Nervous System in Sj(SqrRoot)(Delta)Gren s Syndrome

Background: Sj(SqrRoot)(Delta)gren s Syndrome (SS) is an autoimmune disease that affects the glands that produce saliva and tears, causing dry eyes and dry mouth. Researchers do not know the exact cause of SS, but they believe that it may be caused by abnormalities in the autonomic nervous system (ANS) that stimulate these glands. Objectives: To better understand ANS function in patients with SS. To compare information about ANS function in healthy individuals and in patients with SS. Eligibility: Patients with Sj(SqrRoot)(Delta)gren s Syndrome who are 18 years of age and older, and who are not pregnant or breastfeeding. Participants will be asked to taper or discontinue the use of certain medications or dietary supplements before the ANS testing. Participants must be willing to discontinue the use of alcohol and tobacco 24 hours prior to testing. Design: The study will require one inpatient admission and/or outpatient visits to the NIH Clinical Center. The following tests and procedures will be performed: * Saliva, tear, and sweat production measurements to evaluate the function of glands. * Testing of changes to the cardiovascular system, including blood pressure and blood flow testing, and an electrocardiogram designed to evaluate hemodynamic changes controlled by the ANS. * Testing of changes to the gastrointestinal system, including a swallowing assessment study, barium swallow study, and gastric emptying study designed to evaluate gastrointestinal function controlled by the ANS. * Tests to evaluate the ANS function in response to certain drugs (edrophonium, glucagon and acetylcholine). * Self-reported questionnaire on ANS function and emotional/psychological well-being. Additional procedures and tests may include the following: * Blood samples. * Optional skin biopsy to study sweat glands and nerve supply of the skin.