Electrotonic junctions in cecropia moth ovaries

The steady-state potential of the oocyte, resistance between the ooplasm and the medium, and electronic coupling between oocytes in adjacent follicles were examined in vitellogenic ovarioles of Hyalophora cecropia. The steady-state potential had a constant value of −40 mV throughout the 100-fold vol...

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Bibliographic Details
Published inDevelopmental biology Vol. 69; no. 1; pp. 281 - 295
Main Author Woodruff, Richard I.
Format Journal Article
LanguageEnglish
Published United States Elsevier Inc 01.01.1979
Subjects
Animals
Electrophysiology
Female
Fluoresceins - metabolism
Hyalophora cecropia
Lepidoptera - physiology
Membrane Potentials
Moths - physiology
Oocytes - physiology
Oocytes - ultrastructure
Oogenesis
Ovary - physiology
Ovary - ultrastructure
Ovum - physiology
Vitellogenins - biosynthesis
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Summary:The steady-state potential of the oocyte, resistance between the ooplasm and the medium, and electronic coupling between oocytes in adjacent follicles were examined in vitellogenic ovarioles of Hyalophora cecropia. The steady-state potential had a constant value of −40 mV throughout the 100-fold volume increase accompanying yolk deposition, while membrane resistance decreased gradually with increasing size. Resistance rose steeply with the onset of chorion deposition, but did not detectably change with either nurse cell collapse or termination of vitellogenesis. Nonrectified electrical coupling was found between oocytes in adjacent follicles, and fluorescein ions injected into the ooplasm moved readily from follicle to follicle. Large surface area and low membrane resistance made coupling difficult to detect electrically between more mature oocytes, but interfollicular fluorescein migration was found to persist until the end of vitellogenesis. Migration of fluorescein from the oocyte to the follicular epithelium could also be visualized and fingers of ooplasm that cross the vitelline envelope and terminate in dome-shaped attachments to the epithelial cells were implicated in this transfer. The termination of interfollicular coupling coincided with the termination of epithelial-oocyte coupling, and is proposed to result from thickening of the vitelline envelope and withdrawal of the ooplasmic processes.
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SourceType-Scholarly Journals-1
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ISSN:0012-1606
1095-564X
DOI:10.1016/0012-1606(79)90292-6