Conductance rise induced by the calcium ionophore A23187 in unfertilized eggs of tilapia.
Current-clamp measurements on unfertilized tilapia eggs gave linear current-voltage relations in the range 0 to -120 mV. Eggs had low resting potentials (-22 mV) and high specific membrane resistances (500 k omega cm2) and specific membrane capacitances (0.9 microF cm-2) indicating no marked folding of their plasma membrane. Application of A23187 induced a small depolarization and a conductance rise, the response having a reversal potential of about -16 mV. The results suggest that tilapia eggs have a calcium-gated conductance probably activated at fertilization.
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Laboratoire de Physiologie Cellulaire et Comparée, Faculté des Sciences, Université de Nice, Sophia Antipolis, France.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D004553:Electric Conductivity / Q000187:drug effects; D005260:Female; D007473:Ion Channels / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D010063:Ovum / Q000502:physiology*; D010473:Perciformes
D007473:Ion Channels; D000001:Calcimycin; D002118:Calcium