. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CALMODULIN AND SPISULA OOCYTES 47 100 80 Q CO S 60 LL) Q_ 40 20. TIME OF ADDITION (min) FIGURE 3. Time of sensitivity to W-7 and verapamil of KCl-induced GVBD in Spisula oocytes. Oocytes were exposed to 6% M KG at T = 0 min and 100 nM W-7 (filled circles) or 75 verapamil (open circles) was added at the times indicated. Oocytes were examined for GVBD 20 min after KG addition. The times of addition at which GVBD was inhibited 50% were determined using curve-fitting software to be ± min for W-7 and ±
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CALMODULIN AND SPISULA OOCYTES 47 100 80 Q CO S 60 LL) Q_ 40 20. TIME OF ADDITION (min) FIGURE 3. Time of sensitivity to W-7 and verapamil of KCl-induced GVBD in Spisula oocytes. Oocytes were exposed to 6% M KG at T = 0 min and 100 nM W-7 (filled circles) or 75 verapamil (open circles) was added at the times indicated. Oocytes were examined for GVBD 20 min after KG addition. The times of addition at which GVBD was inhibited 50% were determined using curve-fitting software to be ± min for W-7 and ± min for verapamil. These times were significantly different from each other by the Mest (P < ). occurred in CFSW and CMFSW as well as in ASW and occurred whether or not oocytes had been previously inseminated or stimulated with KC1 but only if the ger- minal vesicles had not broken down (data not shown). Examples of the kind of con- tractions and deformations observed are shown in Figure 4c, d, e. In many cases, these severe contractions obliterated the germinal vesicles (cf. Fig. 4e). Observation of ameboid contractions suggested activation of a microfilament-de- pendent cytoplasmic contractile system. To test this, we simultaneously treated oocytes with 75 \iM chlorpromazine and various concentrations of cytochalasin B (CB). As illustrated by Figure 4f, jug/m' CB prevented the ameboid contractions. This treat- TABLE I Ineffectiveness of calmodulin antagonists at inhibition of GVBD induced by ionophore A23187 Antagonist1 GVBD ±SD none 98 2 calmidazolium 100 1 W-7 83 12 W-5 84 8 chlorpromazine 95 3 no ionophore 3 1 1 Chlorpromazine, W-7, and W-5 were 100 fiM; calmidazolium was 10 pM. Three experiments were performed. ionophore A23187 was. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ma
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
