In vivo evidence that protease-activated receptors 1 and 2 modulate gastrointestinal transit in the mouse.
1. Protease-activated receptors (PARs) 1 and 2 modulate the gastric and intestinal smooth muscle motility in vitro. In the present study, we examined if activation of PAR-2 and PAR-1 could alter gastrointestinal transit in mice. 2. Intraperitoneal administration of the PAR-2-activating peptide SLIGRL-NH(2), but not the inactive control LSIGRL-NH(2), at 1 - 5 micromol kg(-1), in combination with the aminopeptidase inhibitor amastatin at 2.5 micromol kg(-1), facilitated gastrointestinal transit in a dose-dependent manner. The human PAR-1-derived peptide SFLLR-NH(2) and the specific PAR-1 agonist TFLLR-NH(2), but not the inactive control FSLLR-NH(2), at 2.5 - 10 micromol kg(-1), in combination with amastatin, also promoted gastrointestinal transit. 3. The Ca2+-activated, small conductance K+ channel inhibitor apamin at 0.01 micromol kg(-1) significantly potentiated the actions of SLIGRL-NH(2) and TFLLR-NH(2) at subeffective doses. 4. The increased gastrointestinal transit exerted by either SLIGRL-NH(2) at 5 micromol kg(-1) or TFLLR-NH(2) at 10 micromol kg(-1) was completely abolished by the L-type Ca2+ channel inhibitor verapamil at 61.6 micromol kg(-1). In contrast, the tyrosine kinase inhibitor genistein at 18.5 micromol kg(-1) failed to modify the effects of the agonists for PAR-2 or PAR-1. 5. These findings demonstrate that PAR-1 and PAR-2 modulate gastrointestinal transit in mice in vivo. Our data also suggest that the PAR-1-and PAR-2-mediated effects are modulated by apamin-sensitive K+ channels and are dependent on activation of L-type Ca2+ channels, but independent of tyrosine kinase. Our study thus provides novel evidence for the physiological and/or pathophysiological roles of PARs 1 and 2 in the digestive systems, most probably during inflammation.
Kawabata
A
A
Department of Pathophysiology & Therapeutics, Faculty of Pharmaceutical Sciences, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan. kawabata@phar.kindai.ac.jp
Kuroda
R
R
Nagata
N
N
Kawao
N
N
Masuko
T
T
Nishikawa
H
H
Kawai
K
K
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001030:Apamin / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005769:Gastrointestinal Motility / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects; D051379:Mice; D009842:Oligopeptides / Q000494:pharmacology; D010455:Peptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D018179:Receptors, Thrombin / Q000819:agonists / Q000378:metabolism*; D014700:Verapamil / Q000494:pharmacology
D000900:Anti-Bacterial Agents; C090291:C186 65; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D009842:Oligopeptides; D010455:Peptides; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D018179:Receptors, Thrombin; C112356:seryl-leucyl-isoleucyl-glycyl--arginyl-leucinamide; D001030:Apamin; C016977:amastatin; D014700:Verapamil; D019833:Genistein; D011505:Protein-Tyrosine Kinases