. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. t Ref. * upward I downward 5mm DILTIAZEM. tV2 V3 Figure 4A-B. (A) Current density profile at the vegetal pole (V) of a Lynmaea egg perfused with 2 mM diltiazem in CFTW at early telophase (VI) of the first meiotic division. The current decreased within 10%> of the cell cycle (V2) and disappeared within 25% of the cell cycle (V3). Note that after perfusion with diltiazem the current density scale changed due to the lower resistivity of this medium. (B) The current density profile at the animal (A) and vegetal (V) pole of an
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. t Ref. * upward I downward 5mm DILTIAZEM. tV2 V3 Figure 4A-B. (A) Current density profile at the vegetal pole (V) of a Lynmaea egg perfused with 2 mM diltiazem in CFTW at early telophase (VI) of the first meiotic division. The current decreased within 10%> of the cell cycle (V2) and disappeared within 25% of the cell cycle (V3). Note that after perfusion with diltiazem the current density scale changed due to the lower resistivity of this medium. (B) The current density profile at the animal (A) and vegetal (V) pole of an egg incubated in mM D600 in CFTW + 2 mA/CaCN. Incubation was initiated 20 min prior to first meiotic anaphase in the controls. A maximum density of about 170 nA/cm2 was measured at telophase (V2) of the first meiotic cell cycle. However, this maximum density was reduced if compared to the controls in medium without D600. Note that the current is outward (downward) at the vegetal pole (V), and inward (downward) at the animal pole (A). peak is not associated with maximum bulging out of the polar bodies as in the controls, but occurs a few minutes later. This suggests that other ions than calcium are also components of the ionic current. We do not know if the currents described here are causally related to the animal-vegetal polarity of the egg. However, some interesting correlations between polar events in the egg and current pattern have emerged from this study. First, the absence of current at the animal pole before first polar body formation (Fig. 2A) coincides with a stage during which animal/vegetal polarity is not yet firmly established, as shown in another mollusc, Umax (Guerrier, 1968). Second, the onset of the inward current at the animal pole just before first polar body formation (Fig. 2A) coincides with the anchoring of the meiotic as- ter at the animal pole. This might be the trigger for the increase of ion fluxes there. Third, there is a significant temporal co
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
