Immunohistochemical expression and distributionof orexin, orphanin and leptin in the major salivaryglands of some mammals

The aim of the study was to determine by immunochemistry the expression of leptin, orexin A andorphanin FQ in the major salivary glands (parotid, submandibular and sublingual) of rat, sheep and cow. Thesepeptides, originally synthesized in central nervous system, adipose tissue and peripheral tissues including gastrointestinaltract, play an orexigenic (orphanin and orexin) or anorexigenic (leptin) roles in the intricate neuronalnetwork appointed to the control of nutritional homeostasis. Peptide-specific immunoreactivity was presentin the studied salivary glands with various intensities in different species, in the ductal epithelium, sometimes inthe acinar epithelium, and in nervous trunks spread in connective tissue stroma. The obtained data show thatsalivary glands present an unexpected source of orexigenic and anorexigenic peptides which with their autocrine,paracrine, and endocrine mechanisms of action may participate in the control of salivary gland function.