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

Rod‐Shaped Nanocrystals Elicit Neuronal Activity In Vivo

“…Two GJC‐blocking reagents were used to rapidly modify GJ states in living polyps, namely heptanol and anandamide. They have been tested on electrical and chemical GJC in both connexin and innexin‐based GJ 33–36 . H. vulgaris were exposed for 1 h to drugs dissolved in the medium at working concentrations that were sufficiently low to cause no effects on the polyps' physiology, as determined by macroscopic observation.…”

“…Pure heptanol (heptan‐1‐ol), diluted in Sol Hy, was added at a final dilution equal to 3 × 10 −5 ; anandamide (arachidonoylethanolamide), kindly provided by Dr V. Di Marzo (Institute of Biomolecular Chemistry, Pozzuoli, Italy), was diluted to working concentrations (1 µ M ) from a stock (5 m M ). The doses of the drugs used were within the range of magnitude of the doses used to modulate GJ in either vertebrate or invertebrate organisms33–36. In these set of experiments the effect of QRs at a single concentration (7 n M ) was evaluated.…”

Gap Junction Channels of Innexins and Connexins: Relations and Computational Perspectives

“…When using octanol for inhibiting GJC, connexon downregulation was demonstrated in different insects, like Oncopeltus, Hyalophora, Drosophila, Xylocopa, and Periplaneta [60,61,62,63]. In addition, GJC was inhibited in rodents to better understand the function of proteins and transcriptional regulators, as well as the mechanism of function of these inhibitors on cell communication [64,65,66].…”