Ratiometric calcium concentration estimation using LED excitation during mechanotransduction in single sensory neurons

Contributions of Voltage- and Ca2+-Activated Conductances to GABA-Induced Depolarization in Spider Mechanosensory Neurons

“…1. Resting [Ca 2ϩ ] in the present experiments was 144.9 Ϯ 139 nM (mean Ϯ SD, n ϭ 22), somewhat higher than reported previously (67.3 nM; Höger et al 2007). After GABA or muscimol treatment [Ca 2ϩ ] increased to 399.8 Ϯ 325.2 nM (mean Ϯ SD, n ϭ 7), close to the previously reported saturated concentration of 400 nM in these cells (Höger et al 2007).…”

“…1). Ratiometric Ca 2ϩ measurements were performed using Fura-Red, tetrapotassium salt (10 mM in 2 M KCl; Invitrogen, Burlington, ON, Canada) as described before (Höger et al 2007). Cells were loaded iontophoretically through the glass microelectrodes and visualized with epifluorescence optics (XF2009 dichroic beam splitter and XF3012 emission filter; Omega Optical, Brattleboro, VT).…”

“…VS-3 neuron intracellular [Ca 2ϩ ] was previously shown to increase in response to action potential firing when the neurons were stimulated by repeated mechanical steps (Höger et al 2007). Here, we used 15-Hz mechanical stimulation in 18 experiments to produce action potentials and observed a mean rise of 0.27 in the fluorescence ratio (Fig.…”

“…Linear fits to the data indicate that the reversal potentials were Ϫ37 and Ϫ21 mV for the control data and the Ni 2ϩ -treated data, respectively. previous report (Höger et al 2007), the actual Ca 2ϩ concentration was estimated using Eq. 1.…”

Calcium buffering and clearance in spider mechanosensory neurons

“…current (Sekizawa et al 2000), and their intracellular [Ca 2? ] rises significantly during action potential firing and also when the neurons are depolarized by agonists of GABA A (c-aminobutyric acid) receptors (Höger et al 2007;Panek et al 2008). Previous evidence suggests that intracellular Ca 2?…”