Activation of prostacyclin synthesis by mechanical stimulation in the ciliated protozoan Tetrahymena thermophila.
We detected a HPLC peak corresponding to 6-keto-PGF(1alpha), a stable metabolite of prostacyclin (PGI(2)), in [1-(14)C]arachidonate metabolites from the ciliated protozoan Tetrahymena thermophila. Quantitative analysis of 6-keto-PGF(1alpha) by enzyme immunoassay revealed that the synthesis and release were rapidly activated by the mechanical stimulation of a short centrifugation. The activation was suppressed significantly by a cyclooxygenase inhibitor, ibuprofen, and was independent of the extracellular Ca(2+). External addition of PGI(2) and its stable analogue, beraprost, caused a transient increase in the tumbling frequency of swimming. Other prostanoids, PGE(2) and PGF(2alpha), have no effect on the swimming. These results indicate that a free-living ciliate, T. thermophila, synthesizes and has a specific sensitivity to PGI(2).
Iwamoto
M
M
Division of Biophysical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, 560-8531, Japan.
Murata
T
T
Morii
H
H
Watanabe
Y
Y
Nakaoka
Y
Y
D015121:6-Ketoprostaglandin F1 alpha / Q000032:analysis; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D011464:Epoprostenol / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007700:Kinetics; D009068:Movement / Q000187:drug effects / Q000502:physiology; D010812:Physical Stimulation; D011453:Prostaglandins / Q000494:pharmacology*; D016808:Tetrahymena thermophila / Q000187:drug effects / Q000502:physiology*
D002250:Carbon Radioisotopes; D011453:Prostaglandins; D016718:Arachidonic Acid; D015121:6-Ketoprostaglandin F1 alpha; D006160:Guanosine Triphosphate; D011464:Epoprostenol