Inhibition of sea urchin fertilization by fatty acid ethanolamides and cannabinoids.

The influence of saturated and unsaturated fatty acid ethanolamides as well as delta9-tetrahydrocannabinol (delta9-THC), WIN 55,212-2 and cannabinoid CB1 receptor antagonist SR 141716 on sea urchin fertilization was studied. The ethanolamides of arachidonic, oleic and linoleic acids but not saturated fatty acid (C14-C20) derivatives inhibited fertilization when pre-incubated with sperm cells. Delta9-THC and WIN 55,212-2 also inhibited fertilization, delta9-THC being ten times as potent as WIN 55,212-2. Selective cannabinoid CB1 receptor antagonist SR 141716 also blocked fertilization and did not antagonize the action of delta9-THC. The obtained results indicate that different unsaturated fatty acid ethanolamides may control sea urchin fertilization, and that sea urchin sperm cell cannabinoid receptor may differ from the known cannabinoid receptor subtypes.