TY - JOUR
T1 - Vasoconstriction induced by zooxanthellatoxin-B, a polyoxygenated long- chain product from a marine alga
AU - Moriya, Takahiro
AU - Ishida, Yukisato
AU - Nakamura, Hideshi
AU - Asari, Tohru
AU - Murai, Akio
AU - Ohizumi, Yasushi
N1 - Funding Information:
We wish to thank Drs. Y. Shigeta and T. Kaneko at the Central Institute, Mitsubishi Chemical, for the use of the atomic absorption spectrophotometer. We also thank Mrs. M. Okamoto of this Department for typing this manuscript. This work was supported in part by a grant of the Scientific Research Fund (No. 05454567) to Y. Ohizumi from the Ministry of Education, Science, Sports and Culture of Japan.
PY - 1998/5/29
Y1 - 1998/5/29
N2 - We found that zooxanthellatoxin-B from a symbiotic marine alga, Symbiodinium sp., caused a concentration-dependent contraction of the rabbit isolated aorta at concentrations of 10-7 10-5 M. Verapamil (10-6 M) and mefenamic acid (10-5 M) significantly attenuated the contractile response to zooxanthellatoxin-B at lower concentrations (10-7 - 10-6 M) but not at higher concentrations (3 X 10-610-5 M). The response to zooxanthellatoxin-B was partly inhibited by phentolamine (10-6 M), whereas it was potentiated by ouabain (10-5 M). Tetrodotoxin (10-6 M), methysergide (10-6 M), chlorpheniramine (10-6 M) or indomethacin (3 X 10-6 M), however, did not affect it. The zooxanthellatoxin-B-induced contraction was abolished by incubation in Ca2+-free solution. The contractile response increased in a concentration-dependent fashion with Ca2+ (0.03 and 10 mM) or Sr2+ (0.10 and 10 mM). After treatment with verapamil (10-6 or 5 X 10-6 M), the concentration-contractile response curves for Ca2+ and Sr2+ in the presence of zooxanthellatoxin-B were shifted to the right in parallel. MgCl2 (10 mM) shifted the concentration- response curve for Ca2+ more markedly than did verapamil. Zooxanthellatoxin-B increased tissue Na+ and reduced tissue K+ contents in the aorta, suggesting that zooxanthellatoxin-B increases Na+ and K+ permeability across the plasma membrane. These results suggest that the zooxanthellatoxin-B-induced contraction of the aorta is caused mainly by a direct action on smooth muscle, i.e., an increase in Ca2+ permeability that occurs at least partly through voltage-sensitive Ca2+ channels as well as through nonselective cation channels in the cell membrane of smooth muscle.
AB - We found that zooxanthellatoxin-B from a symbiotic marine alga, Symbiodinium sp., caused a concentration-dependent contraction of the rabbit isolated aorta at concentrations of 10-7 10-5 M. Verapamil (10-6 M) and mefenamic acid (10-5 M) significantly attenuated the contractile response to zooxanthellatoxin-B at lower concentrations (10-7 - 10-6 M) but not at higher concentrations (3 X 10-610-5 M). The response to zooxanthellatoxin-B was partly inhibited by phentolamine (10-6 M), whereas it was potentiated by ouabain (10-5 M). Tetrodotoxin (10-6 M), methysergide (10-6 M), chlorpheniramine (10-6 M) or indomethacin (3 X 10-6 M), however, did not affect it. The zooxanthellatoxin-B-induced contraction was abolished by incubation in Ca2+-free solution. The contractile response increased in a concentration-dependent fashion with Ca2+ (0.03 and 10 mM) or Sr2+ (0.10 and 10 mM). After treatment with verapamil (10-6 or 5 X 10-6 M), the concentration-contractile response curves for Ca2+ and Sr2+ in the presence of zooxanthellatoxin-B were shifted to the right in parallel. MgCl2 (10 mM) shifted the concentration- response curve for Ca2+ more markedly than did verapamil. Zooxanthellatoxin-B increased tissue Na+ and reduced tissue K+ contents in the aorta, suggesting that zooxanthellatoxin-B increases Na+ and K+ permeability across the plasma membrane. These results suggest that the zooxanthellatoxin-B-induced contraction of the aorta is caused mainly by a direct action on smooth muscle, i.e., an increase in Ca2+ permeability that occurs at least partly through voltage-sensitive Ca2+ channels as well as through nonselective cation channels in the cell membrane of smooth muscle.
KW - Aorta
KW - Ca channel
KW - Contraction
KW - Rabbit
KW - Smooth muscle
KW - Zooxanthellatoxin-B
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U2 - 10.1016/S0014-2999(98)00225-8
DO - 10.1016/S0014-2999(98)00225-8
M3 - Article
C2 - 9683015
AN - SCOPUS:0032577683
VL - 350
SP - 59
EP - 65
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
SN - 0014-2999
IS - 1
ER -