Premium
Electronic‐endoscopic Observation of ET‐1 Induced Mucosal Ischemia and Preventive Effect of ETA Recepter Selective Antagonist, FR139317, in Rat Distal Colon
Author(s) -
HOSOKAWA Masaya,
TOMINAGA Masayuki,
UEDA Syunji,
TANIGUCHI Takao,
NAKAMURA Hiroshi,
TSUKADA Hideaki,
OKUMA Mimoru,
SAKAI Masahiko
Publication year - 1995
Publication title -
digestive endoscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.5
H-Index - 56
eISSN - 1443-1661
pISSN - 0915-5635
DOI - 10.1111/j.1443-1661.1995.tb00170.x
Subject(s) - medicine , microcirculation , pathophysiology , blood flow , antagonist , ischemia , laser doppler velocimetry , gastroenterology , urology , endocrinology , receptor
For investigation of the effects of Endothelin‐1 (ET‐1) on colonic mucosa, ET‐1 (10–160 nmol/kg) was sprinkled on rat colonic mucosa under observation with a new electronic endoscopic system (TOSHIBA TRE‐3000, Japan). A high dose of ET‐1 induced complete obstruction of submucosal arterioles, but not venules, without affecting arterial blood pressure. The ET‐1 ‐induced contraction of both vessel types was maintained for 50 min and was followed by intramucosal dot hemorrhages. In this experimental model, the effects of ET‐1 on the mucosal microcirculation were further analyzed with a laser doppler blood flowmeter (LDF) during endoscopic observation. The maximum decrease in mucosal blood flow was to 20 % of the control value and this decrease was maintained for 20 min at a dose of 80 nmol/kg. An ETA receptor selective antagonist, FR139317 (800 nmol/kg), inhibited ET‐1 ‐induced changes in endoscopic findings and LDF, shifting the concentration‐response curve of LDF to the right. FR139317 is a potentially useful new therapy for inflammatory bowel diseases, conditions which have been reported to be associated with high local concentrations of ET‐1. Our electronic‐endoscopic system was demonstrated to be a useful basic research tool for studying gastrointestinal pathophysiology.