We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Inhibitory mechanism of xestospongin-C on contraction and ion channels in the intestinal smooth muscle.
- Authors
Ozaki, Hiroshi; Hori, Masatoshi; Kim, Yoon-Sun; Kwon, Seong-Chun; Ahn, Duck-Sun; Nakazawa, Hiroshi; Kobayashi, Motomasa; Karaki, Hideaki
- Abstract
1 Xestospongin-C isolated from a marine sponge, Xestospongia, sp., has recently been shown to be a membrane-permeable IP[SUB3] receptor inhibitor. In this study we examined the effects of this compound on smooth mascle from guinea-pig ileum. 2 In guinea-pig ileum permeabilized with α-toxin, xestospongin-C (3 μM) inhibited contractions induced by Ca[SUP2+] mobilized from sarcoplasmic reticulum (SR) with IP[SUB3] or carbachol with GTP, but not with caffeine. 3 In intact smooth muscle tissue, xestospongin-C (3-10 μM) inhibited carbachol- and high-K[SUP+]induced increases in [Ca[SUP2+]][SUBi] and contractions at sustained phase 4 It also inhibited voltage-dependent inward Ba[SUP2+] currents in a concentration-dependent manner with an IC[SUB50] of 0.63 μM. Xestospongin-C (3-10 μM) had no effect on carbachol-induced inward Ca[SUP2+] currents via non-selective cation channels: but it did reduce voltage-dependent K[SUP+] currents in a concentration-dependent manner with an IC[SUB50] of 0.13 μM. 5 These results suggest that xestospongin-C inhibits the IP[SUB3] receptor but not the ryanodine receptor in smooth muscle SR membrane. In intact smooth muscle cells, however, xestospongin-C appears to inhibit voltage-dependent C[SUP2+] and K[SUP+] currents at a concentration range similar to that at which it inhibits the IP[SUB3] receptor. Xestospongin-C is a selective blocker of the IP[SUB3] receptor in permeabilised cells but not in cells with intact plasma membrane.
- Subjects
SMOOTH muscle; ION channels; INOSITOL
- Publication
British Journal of Pharmacology, 2002, Vol 137, Issue 8, p1207
- ISSN
0007-1188
- Publication type
Article
- DOI
10.1038/sj.bjp.0704988