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

Abstract

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.

Mathematical model of morphogen electrophoresis through gap junctions

“…Roles for electrophoretic movement of morphogens (Cooper, 1984;Cooper et al, 1989;Fear and Stuchly, 1998a-c) have been proposed previously, in the context of follicle-egg systems (Woodruff and Telfer, 1980;Telfer et al, 1981;Bohrmann and Gutzeit, 1987;Woodruff et al, 1988;Woodruff and Cole, 1997;Adler and Woodruff, 2000), self-electrophoresis in Fucus symmetry-breaking (Jaffe et al, 1974;Jaffe and Nuccitelli, 1977), and regeneration in both vertebrate and invertebrate systems (Rose, 1966(Rose, , 1970Smith, 1967;Lange and Steele, 1978). The data on LR patterning suggest a mechanism consistent with this class of models, as applied to a GJC-coupled cell field.…”

Long-range neural and gap junction protein-mediated cues control polarity during planarian regeneration

“…Among n-alcohols, heptanol and octanol are best known for their potent and specific inhibition of GJC in vertebrate and invertebrate models (Adler and Woodruff, 2000; Anderson and Woodruff, 2001; Brooks and Woodruff, 2004; Chanson et al, 1989; Christ et al, 1999; Ehrlich and Diez, 2003; Garcia-Dorado et al, 1997; Mire et al, 2000; Momose-Sato et al, 2005; Waksmonski and Woodruff, 2002; Weingart and Bukauskas, 1998). In planarians, treatment with heptanol or octanol, but not hexanol (which does not block GJC), leads to a consistent alteration of A/P polarity during regeneration, suggesting that the effects of these compounds on planarian regeneration correlate with their ability to block GJs ((Nogi and Levin, 2005), Supplemental Figure 1C).…”

Involvement of cAMP and calmodulin in endocytic yolk uptake duringXenopus laevisoogenesis

“…It should be noted that 1 mM octanol has been often used to disrupt dye coupling between oocytes and their surrounding epithelial cells (Cerdá et al, 1993;Patiño & Purkiss, 1993;Adler & Woodruff, 2000).…”