Steady-state potentials in ovarian follicles of a moth, Hyalophora cecropia

Woodruff, Richard I.; Münz, Axel; Telfer, William H.

doi:10.1016/0022-1910(92)90021-5

Cited by 20 publications

(14 citation statements)

References 30 publications

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“…For Hyalophora we chose females in the 18th day of the pupiladult molt (Telfer, 1965). Hyalophora PSS consisted of 40 mM KCl, 15 mM MgCl 2 , 5 mM CaCl 2 , 110 mM Tris succinate, pH 6.5, and 5 mM phenylthiourea (Anderson and Telfer, 1969;Hausman et al, 1971) adjusted with sucrose to 300 mOsmol (Woodruff et al, 1992). Females were dissected in the appropriate physiological salt solution (PSS) for each species.…”

Section: Methodsmentioning

confidence: 99%

Varied effects of 1‐octanol on gap junctional communication between ovarian epithelial cells and oocytes of Oncopeltus fasciatus, Hyalophora cecropia, and Drosophila melanogaster

Adler¹,

Woodruff²

2000

Arch. Insect Biochem. Physiol.

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In insect gap junctions, species-specific differences occur in response to the purported gap junction uncoupling agent, 1-octanol. Changes in gap junctional communication between oocytes and their epithelial cells following treatment with 1-octanol were assayed in Oncopeltus fasciatus (the milkweed bug), Hyalophora cecropia (the American silk moth), and Drosophila melanogaster. In all three species, microinjection of untreated control follicles with Lucifer yellow CH revealed extensive dye coupling among epithelial cells and between epithelial cells and their oocytes. Also for all three species, treatment with octanol appeared to completely block dye coupling and increase oocyte input resistance. The effect on electrical coupling varied. In Drosophila, octanol diminished the electrical coupling from 64% (0.64 coupling coefficient) in controls to 53% in treated follicles. In Hyalophora, the coupling ratio remained the same following treatment. In Oncopeltus, octanol actually increased the electrical coupling ratio from 84% in controls to 94% in treated follicles. While 0.5 mM octanol left some Oncopeltus epithelial cells dye coupled to the oocyte, the electrical coupling ratio was increased slightly more by this concentration than by 1 or 5 mM octanol solutions, although the differences were not significant. While input resistance (R(o )) increased in all three following treatment with octanol, there was considerable difference in the magnitude of the response. Average oocyte R(o ) for Oncopeltus increased the least of the three species, rising from 196-240 kOhm. Both Hyalophora, with a nearly fourfold increase from 230-900 kOhm or more, and Drosophila, with a twofold increase from 701 kOhm to over 1.2 MegOhm showed much larger changes. Results shown here indicate that insect gap junctions have more varied responses to this common gap junction antagonist than have been reported for their vertebrate counterparts. Arch.

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Section: Methodsmentioning

confidence: 99%

Varied effects of 1‐octanol on gap junctional communication between ovarian epithelial cells and oocytes of Oncopeltus fasciatus, Hyalophora cecropia, and Drosophila melanogaster

Adler¹,

Woodruff²

2000

Arch. Insect Biochem. Physiol.

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“…The average difference (nurse cell Em-oocyte Em = Ebridge) was -8.3 & .7 mV and was significant to the 0,0001 level by paired t-test. The average input resistance of these follicles, determined by pulsing current into the oocyte, was 483 2 52 kfl, comparable to measurements obtained in earlier studies [8]. (It is the input resistance of the entire follicle, including the oocyte membrane in parallel with that of the epithelium, which is linked to the oocyte by gap junctions, and of the nurse cells, which are linked to it by the intercellular bridges.…”

Section: Transbridge Potentialmentioning

confidence: 67%

“…It is important to note, however, that EM in the vitellogenic follicle is accounted for primarily by electrochemical gradients of K+ and H+, and only -30% by electrogenic pumps [8]. Whereas the latter have not yet been defined, Ca2' extrusion is clearly a possible component.…”

Section: Discussionmentioning

confidence: 98%

“…Variably gated Ca2+ channels are therefore present in this system, although to detect them it was necessary to block K' channels with triethanolamine and Ba2 +. Permeability to divalent cations is normally low, however, for neither Ca2+ nor M$+ replacement in the incubation medium affected EM between the oocyte and the medium [8].…”

Section: Discussionmentioning

confidence: 99%

“…(Wescor, Logan, UT), by the addition of sucrose [8]. To inhibit the polyphenol oxidase of this system, 5 mM phenylthiourea (PTU) was added to the medium used during dissection.…”

Section: Materials and Methods Folliclesmentioning

confidence: 99%

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Steady‐state gradient in calcium ion activity across the intercellular bridges connecting oocytes and nurse cells in Hyalophora cecropia

Woodruff

Telfer

1994

Arch Insect Biochem Physiol

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Intracellular activities of K+, H+, Mg2+, Ca2+, and Cl-, measured with ion selective microelectrodes in the oocyte and the nurse cells in ovarian follicles of Hyalophora cecropia, indicated that a Ca2+ current is a key component of the electrical potential that is maintained across the intercellular bridges connecting these two cells. In vitellogenic follicles, Ca2+ activity averaged 650 nM in the oocyte and 190 nM in the nurse cells, whereas activities of the other ions studied differed between these cells by no more than 6%. Incubation in 200 microM ammonium vanadate caused a reversal of electrical potential from 8.3 mV, nurse cell negative, to 3.0 mV, oocyte negative, and at the same time the Ca2+ gradient was reversed: activities rose to an average 3.0 microM in the nurse cells and 1.6 microM in the oocyte, whereas transbridge ratios of the other cations remained at 0-3%. In immature follicles that had not yet initiated their transbridge potentials, Ca2+ activities averaged approximately 2 microM in both oocyte and nurse cells. The results suggest that vitellogenic follicles possess a vanadate-sensitive Ca2+ extrusion mechanism that is more powerful in the nurse cells than in the oocyte.

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Varied effects of 1-octanol on gap junctional communication between ovarian epithelial cells and oocytes ofOncopeltus fasciatus,Hyalophora cecropia, andDrosophila melanogaster

Adler

Woodruff

2000

Arch. Insect Biochem. Physiol.

View full text Add to dashboard Cite

In insect gap junctions, species‐specific differences occur in response to the purported gap junction uncoupling agent, 1‐octanol. Changes in gap junctional communication between oocytes and their epithelial cells following treatment with 1‐octanol were assayed in Oncopeltus fasciatus (the milkweed bug), Hyalophora cecropia (the American silk moth), and Drosophila melanogaster. In all three species, microinjection of untreated control follicles with Lucifer yellow CH revealed extensive dye coupling among epithelial cells and between epithelial cells and their oocytes. Also for all three species, treatment with octanol appeared to completely block dye coupling and increase oocyte input resistance. The effect on electrical coupling varied. In Drosophila, octanol diminished the electrical coupling from 64% (0.64 coupling coefficient) in controls to 53% in treated follicles. In Hyalophora, the coupling ratio remained the same following treatment. In Oncopeltus, octanol actually increased the electrical coupling ratio from 84% in controls to 94% in treated follicles. While 0.5 mM octanol left some Oncopeltus epithelial cells dye coupled to the oocyte, the electrical coupling ratio was increased slightly more by this concentration than by 1 or 5 mM octanol solutions, although the differences were not significant. While input resistance (Ro ) increased in all three following treatment with octanol, there was considerable difference in the magnitude of the response. Average oocyte Ro for Oncopeltus increased the least of the three species, rising from 196–240 kOhm. Both Hyalophora, with a nearly fourfold increase from 230–900 kOhm or more, and Drosophila, with a twofold increase from 701 kOhm to over 1.2 MegOhm showed much larger changes. Results shown here indicate that insect gap junctions have more varied responses to this common gap junction antagonist than have been reported for their vertebrate counterparts. Arch. Insect Biochem. Physiol. 43:22–32, 2000. © 2000 Wiley‐Liss, Inc.

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Steady-state potentials in ovarian follicles of a moth, Hyalophora cecropia

Cited by 20 publications

References 30 publications

Varied effects of 1‐octanol on gap junctional communication between ovarian epithelial cells and oocytes of Oncopeltus fasciatus, Hyalophora cecropia, and Drosophila melanogaster

Varied effects of 1‐octanol on gap junctional communication between ovarian epithelial cells and oocytes of Oncopeltus fasciatus, Hyalophora cecropia, and Drosophila melanogaster

Steady‐state gradient in calcium ion activity across the intercellular bridges connecting oocytes and nurse cells in Hyalophora cecropia

Varied effects of 1-octanol on gap junctional communication between ovarian epithelial cells and oocytes ofOncopeltus fasciatus,Hyalophora cecropia, andDrosophila melanogaster

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