Activation of protease-activated receptor-2 (PAR-2) triggers mucin secretion in the rat sublingual gland.
Protease-activated receptor-2 (PAR-2) is distributed throughout the gastrointestinal systems. The present study investigated the role for PAR-2 in the rat salivary glands. PAR-2 mRNA was detected in the sublingual, submaxillary, and parotid glands by a reverse-transcriptase polymerase chain reaction. In the isolated sublingual gland that exhibited the strongest signal for PAR-2, Ser-Leu-Ile-Gly-Arg-Leu-NH(2), a PAR-2-activating peptide, and trypsin, a PAR-2-activating enzyme, but not thrombin that can activate PARs 1, 3, and 4, triggered secretion of N-acetylneuraminic acid, an indicator of mucin, that was a unique major sialic acid detectable after hydrolysis of the sublingual mucin with 0.1 N HCl. The PAR-2-mediated secretion of mucin was attenuated by genistein, a tyrosine kinase inhibitor, but not by inhibitors of protein kinase C and phosphatidyl inositol 3'-kinase. Thus, PAR-2 is expressed by the three distinct salivary glands in the rat, and sublingual PAR-2 appears to play a role in triggering mucin secretion, at least in part, via activation of tyrosine kinase.
Kawabata
A
A
Faculty of Pharmaceutical Sciences, Kinki University, Higashi-Osaka, Japan. kawabata@phar.kindai.ac.jp
Morimoto
N
N
Nishikawa
H
H
Kuroda
R
R
Oda
Y
Y
Kakehi
K
K
D000818:Animals; D019833:Genistein / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009077:Mucins / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D044464:Receptor, PAR-2; D018179:Receptors, Thrombin / Q000819:agonists / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism; D013361:Sublingual Gland / Q000378:metabolism*
D009077:Mucins; D009842:Oligopeptides; D000081082:Phosphoinositide-3 Kinase Inhibitors; D044464:Receptor, PAR-2; D018179:Receptors, Thrombin; D012794:Sialic Acids; C099570:seryl-leucyl-isoleucyl-glycyl-arginyl-leucine; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C