Volume changes and whole cell membrane currents activated during gradual osmolarity decrease in C6 glioma cells: contribution of two types of K⁺ channels

Abstract

Ordaz, B., L. Vaca, R. Franco, and H. Pasantes-Morales. Volume changes and whole cell membrane currents activated during gradual osmolarity decrease in C6 glioma cells: contribution of two types of K ϩ channels.

Channels and Volume Changes in the Life and Death of the Cell

“…K 1 conductance is also activated in these cells during IVR with different osmolarity thresholds in the presence or absence of Ca 21 (Ordaz et al, 2004). In a variety of cell types, gradual changes in osmolarity activate taurine efflux with different efflux threshold Souza et al, 2000;Ordaz et al, 2004). The lowest efflux is observed in cerebellar granule neurons where taurine efflux increases significantly at osmolarity reductions of only 2 mOsm (Fig.…”

“…This point should be clarified in light of new findings regarding the LCRR8 family members as integral elements of VRAC. K 1 conductance is also activated in these cells during IVR with different osmolarity thresholds in the presence or absence of Ca 21 (Ordaz et al, 2004). In a variety of cell types, gradual changes in osmolarity activate taurine efflux with different efflux threshold Souza et al, 2000;Ordaz et al, 2004).…”

“…Another member of the TRP channel family, TRPV2, seems to participate in RVI via an interesting connection with the electroneutral cotransporter NKCC, which as previously mentioned is a main effector in RVI. The suggested mechanistic chain of events relating TRPV2 channels and RVI involves a TRPV2-dependent Tuz et al, 2001;Ordaz et al, 2004. accelerated depolarization followed by Ca 21 release from intracellular sources and the subsequent phosphorylation of STE20/SPS1-related proline/alanine-rich kinases (SPAKs), which is essential for activation of NKCC. This proposed pathway is supported by studies in skeletal muscle showing that expression of TRPV2 negative dominant reduces the RVI efficiency at the time that depolarization is impaired and the Ca 21 response is diminished (Zanou et al, 2015).…”

Osmoregulation of Taurine Efflux from Cultured Human Breast Cancer Cells: Comparison with Volume Activated Cl^- Efflux and Regulation by Extracellular ATP

“…Other studies have suggested that volumesensitive taurine efflux does not always utilize anion channels. It is apparent that taurine efflux in Ehrlich Ascites cells [7], lactating rat mammary tissue [8,9], skate erythrocytes [23], supraoptic glial cells [24], C6 glioma cells [25] and cultured human intestinal epithelial cells [26] is independent from volume-activated chloride channels. It is also claimed that volume-activated taurine efflux from some cell types is via an anion exhanger [27].…”

Swelling-Induced Taurine Transport: Relationship with Chloride Channels, Anion-Exchangers and Other Swelling-Activated Transport Pathways

“…see [64]). However, Ordaz et al [65] have shown that C6 glioma cells, exposed to a gradual change in the external osmolality, require a larger decrease to stimulate the release of taurine compared to that required to stimulate an increase in Cl -permeability. Similarly, Tomassen et al [29] have shown that activation of swelling-induced taurine release from cultured human intestinal cells required the medium osmolality to be lowered to 225 mosmoles/kg whereas volume-sensitive I -efflux was activated at 290 mosmoles/kg.…”