Fig. 1: Temporal profile of the [Ca²⁺]_c responses induced by 10 µM icilin in PC3 cells transfected with full-length TRPM8 (PC3-M8).

Changes in cytosolic Ca²⁺ concentration ([Ca²⁺]_c), reported by confocal x-y time-series imaging (at 0.5 Hz) of fluo-4 fluorescence, were elicited by stimulation of TRPM8 with 10 µM icilin in PC3-M8 cells. Traces of the relative changes in fluo-4 fluorescence (ΔF/F₀) in the cells depicted by the numbers (left) are shown from top to bottom, respectively (middle). The galleries (right) show (left to right, top to bottom) every 90^th image captured during the imaging protocol. Note that initial [Ca²⁺]_c transient is followed by [Ca²⁺]_c oscillations persisting for at least 1 h a. Also note that block of TRPM8 with selective inhibitor M8-B (1 µM) completely abolished both, the sustained [Ca²⁺]_c oscillations b, c and the initial [Ca²⁺]_c transient c. The bar diagram plots d–e, right) compare mean signal temporal densities, calculated as signal mass (left:\({\int} {(\Delta } F/F_0)\); cyan: periods of interest) per second for the initial d and the sustained e response in control (CTL; d n = 122; e n = 85) and following TRPM8 inhibition (M8-B; d n = 72; e n = 79). ***P < 0.001 (Student t-test)