Xenopus borealis as an alternative source of oocytes for biophysical and pharmacological studies of neuronal ion channels

Abstract

For the past 30 years, oocytes from Xenopus laevis have been extensively used to express and characterise ion channels in an easily controlled environment. Here we report the first use of oocytes from the closely related species Xenopus borealis as an alternative expression system for neuronal ion channels. Using the two-electrode voltage-clamp technique, we show that a wide variety of voltage- and ligand-gated ion channels have the same channel properties and pharmacological profiles when expressed in either X. laevis or X. borealis oocytes. Potential advantages of the X. borealis oocytes include a smaller endogenous chloride current and the ability to produce more intense fluorescence signals when studied with voltage-clamp fluorometry. Scanning electron microscopy revealed a difference in vitelline membrane structure between the two species, which may be related to the discrepancy in fluorescence signals observed. We demonstrate that X. borealis oocytes are a viable heterologous system for expression of neuronal ion channels with some potential advantages over X. laevis oocytes for certain applications.

Inhibition of acid‐sensing ion channels by diminazene and APETx2 evoke partial and highly variable antihyperalgesia in a rat model of inflammatory pain

“…Two‐electrode voltage clamp was carried out using Xenopus oocytes as previously described (Cristofori‐Armstrong et al, ). cRNA encoding rat ASIC isoforms (1a, 1b, 2a and 3) was synthesized using an mMessage mMachine cRNA transcription kit and healthy stage V–VI oocytes injected with 4–100 ng cRNA per cell.…”

Rhinella marina oocytes: a suitable alternative expression system for functional characterization of aquaglyceroporins

“…Protocols to obtain oocytes from R. marina , the defolliculation technique used, their maintenance, and injection were optimized (see material and methods). In general, the procedure was similar to those reported in the literature for X. laevis, X. boriales, and R. marina 24–28 . R. marina oocytes were injected with cRNA encoding either a human orthodox aquaporin (hAQP1) or T. brucei aquaglyceroporins (TbAQPs), in order to evaluate whether these cells are able to express aquaglyceroporins and are appropriate to perform water and non-charged solutes permeability measurements.…”

Heterologous Protein Expression in the Xenopus Oocyte

“…Oocytes from species other than Xenopus laevis (e.g., X. tropicalis or X. borealis) can be used. They are smaller and harder to inject compared with X. laevis oocytes, but advantages have been noted (Marchant and Parker 2001; Cristofori-Armstrong et al 2015). Xenopus resource centers provide additional strains/lines (Pearl et al 2012).…”