[Effect of xanthnotoxol on contractility of isolated rabbit ileum].
OBJECTIVE
To study the effect of Xanthnotoxol on contractility of isolated rabbit ileum and its relationship with Ca2+.


METHODS
Routine experimental methods for isolated ileum were adopted.


RESULTS
Xanthnotoxol (XT) and Verapamil (Ver) inhibited the contraction of isolated rabbit ileum smooth muscle induced by submaximal concentrations of acetylcholine (ACh) and serotonim (5-TH), with a IC50 value (mumol.L-1) of 10.495 +/- 1.521, 0.428 +/- 0.001 and 18.132 +/- 1.627, 0.249 +/- 0.003, respectively. XT and Ver inhibited the contraction induced by Ca2+ after high K+ depolarization and for noncompetitively antagonist CaCl2 cumulative dose-response curve, the pD'2 value was 4.69 +/- 0.03 and 6.35 +/- 0.10, respectively. XT (10 mumol.L-1) and Ver(0.06 mumol.L-1) inhibited the contraction induced by ACh in Ca(2+)-free medium, while XT (100 mumol.L-1) but not Ver(0.6 mumol.L-1) inhibited the extracellar CA(2+)-dependent contraction induced by ACh.


CONCLUSIONS
XT has a calcium-antagonistic effect which was not similar to that of Ver.
Hu
X
X
Department of Pharmacology, Gannan Medecal College, Ganzhou 341000, Jiangxi, China.
Zhou
L
L
Lian
Q S
QS
Zheng
J
J
Yang
J G
JG
Lai
F
F
D000818:Animals; D019661:Apiaceae / Q000737:chemistry; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004365:Drugs, Chinese Herbal / Q000302:isolation & purification / Q000494:pharmacology*; D005260:Female; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D011817:Rabbits; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D004365:Drugs, Chinese Herbal; D014700:Verapamil