Cell pellets were homogenized in lysis buffer (Tris‐HCl pH 7.4, 1% Triton X100, NaCl 150 mmol/L and EDTA 1 mmol/L) supplemented with a cocktail of protease inhibitors (1:100, Sigma‐Aldrich, Saint Louis, Missouri, USA). For Western blot quantification, 50 μg of protein were electrophoresed on 12% SDS‐PAGE gels and transferred to nitrocellulose membranes. After blocking with 5% non‐fat milk powder in Tris‐buffered saline with 0.05% Tween‐20 (TBST), membranes were incubated overnight at +4°C with the following primary antibodies: rabbit caspase‐3 cleaved (1:1000, Cell Signaling, Danvers, Massachusetts, USA), mouse anti‐Cx47 (1:200, Invitrogen, Waltham, MA, USA), mouse anti‐Cx43 (1:1000, Cell Signaling, Danvers, Massachusetts, USA), rabbit anti‐Cx40 (1:200, Invitrogen, Waltham, MA, USA), mouse anti‐Cx36 (1:200, Invitrogen, Waltham, MA, USA), mouse anti‐Cx32 (1:500, Novex), rabbit anti‐Cx30 (1:200, Invitrogen, Waltham, MA, USA) and rabbit β‐tubulin (1:1000, Cell Signaling, Danvers, Massachusetts, USA). After three washes in TBST, the membranes were incubated with antimouse (1:20000, Jackson, West Grove, PA, USA) and anti‐rabbit HRP‐conjugated (1:50000, Jackson, West Grove, PA, USA) secondary antibodies for 1 hr at RT. Proteins bands were visualized with premixed ready‐to‐use chemiluminescent HRP detection reagent (Millipore, Darmstadt, Germany) according to the manufacturer's instructions and captured with an Uvitec Cambridge Imaging System. The density of each band was quantified using ImageJ analysis software and normalized to β‐tubulin levels measured in the same membranes.