Innervation pattern and Ca2+ signalling in labial salivary glands of healthy individuals and patients with primary Sjogren's syndrome (pSS)

We have characterised the innervation pattern and intracellular Ca2+-signal ling in labial salivary glands (LSG) of 16 patients with primary Sjogren's syndrome (pSS) and 27 healthy controls. Numerous immunoreactive nerve fiber s (IRF) containing vasoactive intestinal peptide (VIP) and pituitary adenyl ate cyclase activating peptide (PACAP) were found around acini, ducts and b lood vessels. Substance P (SP)-, neuropeptide Y-, tyrosine hydroxylase- and nitric oxide synthase-IRF were mainly surrounding ducts and blood vessels. The majority of pSS patients had inflamed LSG and the presence of focal ly mphocytic infiltrates (FI) were more frequent and pronounced as compared wi th healthy controls. In areas with normal or diffusely inflamed LSG tissue, pSS patients demonstrated the same distribution of IRF as healthy controls with similar histology. However, IRF were absent in central areas of FI bo th in pSS and age-matched healthy controls. Although all pSS patients had h yposalivation, stimulation with acetylcholine, norepinephrine, phenylephrin e, isoproterenol, VIP, PACAP, SP, adenosine 5'-triphosphate and uridine 5'- triphosphate induced the same increase in the intracellular free Ca2+ conce ntration in LSG acini from both pSS patients and healthy controls, indicati ng the presence of functional receptor systems in vitro.