Non-specific currents at fertilisation in sea urchin oocytes.
Using the whole-cell voltage-clamp technique to clamp sea urchin oocytes we show that the fertilising spermatozoon triggers an inward current of -521 +/- 56.7 pA (n = 8) at activation. Simultaneously, the plasma membrane depolarises and the conductance increases from 23.4 +/- 1.4 to 40.6 +/- 1.2 nS (n = 8). The I/V curve for the peak activation current is linear and the current reverses between 0 and +20 mV, suggesting a non-specific ion current. Since injection of inositol triphosphate induced an inward current of -1062 +/- 314 pA (n = 4), and the current was inhibited by preloading oocytes with the calcium chelator BAPTA, the non-specific activation current in sea urchin appears to be calcium dependent.
De Simone
M L
ML
Università Federico II, Naples, Italy.
Grumetto
L
L
Tosti
E
E
Wilding
M
M
Dale
B
B
D000818:Animals; D002118:Calcium / Q000502:physiology*; D004229:Dithiothreitol / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects; D005260:Female; D005306:Fertilization / Q000502:physiology*; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D017136:Ion Transport; D008297:Male; D008564:Membrane Potentials; D008845:Microinjections; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D012617:Sea Urchins / Q000196:embryology / Q000502:physiology*; D013084:Sperm-Ovum Interactions / Q000502:physiology; D015053:Zygote / Q000187:drug effects / Q000502:physiology
D004533:Egtazic Acid; D015544:Inositol 1,4,5-Trisphosphate; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium; D004229:Dithiothreitol