![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
I Muramatsu, H Itoh, K Lederis and MD Hollenberg
Department of Pharmacology, Fukui Medical School, Japan.
Epidermal growth factor-urogastrone (murine EGF-URO) caused concentration-dependent contractile responses in preparations of longitudinal and circular smooth muscle derived from guinea pig stomach. The actions of EGF-URO in these two preparations were distinguished in terms of the ability of indomethacin to block EGF-URO- mediated contraction completely in the longitudinal muscle preparation but not in the circular muscle preparation. The EC50 for EGF-URO was 2 to 5 nM in the longitudinal muscle preparations and 20 to 50 nM in the indomethacin-treated circular muscle preparation. The action of EGF-URO in the longitudinal preparation also was inhibited by ibuprofen, aspirin and by anti-inflammatory steroids possessing an 11-beta- hydroxyl; the corresponding steroids lacking the 11-beta-hydroxyl substituent were inactive. In contrast, little or no effect of the anti- inflammatory steroids on the EGF-URO-mediated response was observed in the indomethacin-treated circular muscle preparation. Partial inhibition (about 30%) of the EGF-URO-mediated contraction of the indomethacin-sensitive longitudinal preparation was caused by mepacrine and p-bromophenyl-acylbromide, whereas esculetine, tranylcypromine, prazosin, yohimbine and cyproheptadine had no effect. The action of EGF- URO in both preparations exhibited marked tachyphyllaxis, which could not be attributed either to the production of inhibitory factors or to the disappearance of EGF-URO from the organ bath. The response of both preparations required the presence of extracellular calcium and was inhibited largely (90%, longitudinal preparation) or in part (69%, indomethacin-treated circular preparation) by verapamil.(ABSTRACT TRUNCATED AT 250 WORDS)
This article has been cited by other articles:
|
|
 |
|
  X.-L. Zheng, Y. Gui, K. A. Sharkey, and M. D. Hollenberg Differential Induction of Nitric Oxide Synthase in Rat Gastric and Vascular Smooth Muscle Tissue: Distinct Tissue Distribution and Distinctive Signaling Pathways J. Pharmacol. Exp. Ther., May 1, 1999; 289(2): 632 - 640. [Abstract] [Full Text]
|
|
|
|
|
|
X.-L. Zheng, B. Renaux, and M. D. Hollenberg Parallel Contractile Signal Transduction Pathways Activated by Receptors for Thrombin and Epidermal Growth Factor-Urogastrone in Guinea Pig Gastric Smooth Muscle: Blockade by Inhibitors of Mitogen-Activated Protein Kinase-Kinase and Phosphatidyl Inositol 3'-Kinase J. Pharmacol. Exp. Ther., April 1, 1998; 285(1): 325 - 334. [Abstract] [Full Text]
|
|
|
|
 |
|
 X.-L. Zheng, K. A. Sharkey, and M. D. Hollenberg Induction of nitric oxide synthase in rat gastric smooth muscle preparations Am J Physiol Gastrointest Liver Physiol, November 1, 1997; 273(5): G1101 - G1107. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X.-L. Zheng, S. Mokashi, and M. D. Hollenberg Contractile Action of Ethanol in Guinea Pig Gastric Smooth Muscle: Inhibition by Tyrosine Kinase Inhibitors and Comparison with the Contractile Action of Epidermal Growth Factor-Urogastrone J. Pharmacol. Exp. Ther., July 1, 1997; 282(1): 485 - 495. [Abstract] [Full Text]
|
|
 |
 |
 |
|
 |
 |
 |
