Effects of calcium channel blockers and DCMU on motility and the photophobic response ofGyrodinium dorsum

✍ Scribed by Nils G. A. Ekelund

• Publisher: Springer
• Year: 1989
• Tongue: English
• Weight: 418 KB
• Volume: 151
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00413128

✦ Synopsis

The effects of the calcium channel blockers, verapamil, diltiazem and lanthanum ions and the Ca 2 + dependency on motility as well as the photophobic response (stop-response) of Gyrodinium dorsum were studied. At Ca z + concentrations below 10-3 M, motility was inhibited. La 3 + inhibits the stop-response, in contrast to verapamil and diltiazem. The only calcium channel blocker that increased the amount of non-motile cells was verapamil. The results indicate that motility are Ca 2 + dependent and that the stop-responses of G. dorsum could be affected by extracellular Ca 2+. Effects of the photosynthesis inhibitor (DCMU) on the stop-response was also determined. With background light of different wavelength (614, 658 and 686 nm) the stop-response increased. DCMU inhibited this effect of background light. Negative results with the monoclonal antibody Pea-25 directed to phytochrome and the results with DCMU, indicate that the stop-response of G. dorsum is coupled to photosynthesis rather than to a phytochrome-like pigment. Oxygen evolution, but not cell movement, was completely inhibited by 10 -6 M DCMU.