Proteinase-activated receptor-2 (PAR-2):: regulation of salivary and pancreatic exocrine secretion in vivo in rats and mice

1 Proteinase-activated receptor-2 (PAR-2) is expressed throughout the gastrointestinal tract including the pancreas, and may be involved in digestive functions. The aim of our study was to evaluate a potential role for PAR-2 in regulating salivary and pancreatic exocrine secretion in vivo. 2 PAR-2-activating peptides (PAR-7-APs), but not selective PAR-1-APs, administered intravenously, increased salivary secretion in the mouse or rat; this effect of the PAR-2-APs was unaffected by atropine, phentolamine, propranolol or indomethacin. 3 Secretion (amylase) by rat parotid gland slices in vitro was also stimulated by PAR-2-APs and trypsin, but not by activation of other PARs. 4 PAR-2-APs. administered to rats in vivo, caused a prompt effect on pancreatic exocrine secretion. 5 PAR-2 mRNA, known to be present in pancreatic tissue, was also detected in parotid tissue. 6 Our results indicate that in addition to a potential role in regulating cardiovascular and respiratory functions, PAR-2 may also play a general role in vivo for the direct regulation of glandular exocrine secretion.