• INCLUSION CRITERIA:

  1. Diagnosis of primary Sjogren's syndrome based on American-European Consensus Group Sjogren's syndrome classification criteria or normal volunteers.
  2. Both genders and all minorities.
  3. Age at entry at least 18 and less than 65 years.

EXCLUSION CRITERIA:

1. Exclusion criteria for primary Sjogren's syndrome:

   • Past head and neck radiation therapy
   • Hepatitis C infection
   • AIDS
   • Pre-existing lymphoma
   • Sarcoidosis
   • GVHD
   • Current use of medications (see note below) known to significantly influence the activity of the sympathetic or parasympathetic nervous system if they cannot be held safely at the time of ANS testing
2. Diagnosis of a concomitant autoimmune disorder that would qualify for secondary Sjogren's syndrome
3. No known co-existing diagnosis of ANS dysfunction (for normal volunteers)
4. Medications-requiring diabetes mellitus
5. Diabetic autonomic neuropathy
6. Vitamin B12, folate deficiency, requiring replacement
7. Hepatic failure (AST or ALT greater than 1.5 x upper limit of normal)
8. Renal failure (GFR less than 30 ml/min, as estimated by the MDRD)
9. Congestive heart failure (Class II-IV)
10. Refractory ventricular arrhythmias
11. Symptomatic coronary heart disease
12. Previously established diagnosis of sinus node dysfunction
13. Severe anemia (Hgb less than 8)
14. Psychosis
15. Pregnant or lactating women
16. Women of childbearing potential must have a negative urine or blood test for pregnancy done within 24 hours before any testing involving radioactivity or investigational drug administration.
17. A candidate subject is excluded if, in the judgment of the Principal Investigator, protocol participation would place the subject at substantially increased acute medical risk.
18. Not able to provide informed consent

Medications: A candidate subject is excluded if clinical considerations require that the patient continue treatment with a drug likely to interfere with the scientific results i.e. a tricyclic antidepressant or fludrocortisone. Patients with known or suspected allergy or hypersensitivity to any test drug are excluded from receiving that drug. Patients who must take medications daily in the following categories are excluded: tricyclic antidepressants, beta blockers, barbiturates, if they cannot be safely held during testing. Patients unable to discontinue nicotine or alcohol temporarily are excluded. Patients are not to discontinue any medications before the patient or the patient's physician discusses this with the Principal Investigator, Dr. Nikolov, or the Associate Investigator, Dr. Goldstein. If it is decided that discontinuing medications would be unsafe, then the patient is excluded from the study. Subjects must discontinue use of alcohol and tobacco throughout the period of testing in the protocol.

Herbal Medicines and Dietary Supplements: Certain herbal medicines or dietary supplements are known or suspected to interfere with the experimental results, and such herbal medicines or dietary supplements must be discontinued before enrollment in the study. For many herbal medicines or dietary supplements, the mechanisms of action and therefore the possible effects on the experimental results are unknown. In cases where the subjects wish to continue their herbal medicines or dietary supplements while on study, and search of the available medical literature fails to identify effects that are known or expected to interfere with the experimental results, then the subjects may participate.