The effects of several ion channel blockers and calmodulin antagonists on fertilization-induced acid release and 45Ca2+ uptake in sea urchin eggs.
The effects of calcium antagonists, diltiazem and verapamil, and calmodulin antagonists, chlorpromazine, N-(6-aminohexyl)-1-naphthalenesulfonamide hydrochloride (W-5) and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7), were tested on two responses of the sea urchin egg to insemination: (1) H+ release; (2) Ca2+ uptake. It was found that calcium antagonists inhibited both processes, while calmodulin antagonists only inhibited H+ release but not Ca2+ uptake. Verapamil and diltiazem were effective to inhibit H+ release when added to the egg suspension up to 120 sec and W-7 was effective around 150 sec after insemination. Calcium antagonists became ineffective earlier than W-7 in inhibiting H+ release. A calmodulin-dependent step may thus occur linking the Ca2+ uptake and H+ release. 4,4'-Diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), an anion channel blocker, also inhibited both Ca2+ uptake and H+ release. This result suggests that an uptake of anion(s) occurs along with Ca2+ uptake.
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000032:analysis*; D004110:Diltiazem / Q000494:pharmacology*; D005260:Female; D005306:Fertilization; D006859:Hydrogen / Q000378:metabolism*; D010063:Ovum / Q000378:metabolism; D012617:Sea Urchins / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology*
D001552:Benzazepines; D002147:Calmodulin; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D000584:Amiloride; D006859:Hydrogen; D014700:Verapamil; D004110:Diltiazem; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002118:Calcium