Ryanodine and IP₃ receptor-mediated calcium signaling play a pivotal role in neurological infrared laser modulation

Abstract

Abstract. Pulsed infrared (IR) laser energy has been shown to modulate neurological activity through both stimulation and inhibition of action potentials. While the mechanism(s) behind this phenomenon is (are) not completely understood, certain hypotheses suggest that the rise in temperature from IR exposure could activate temperature-or pressure-sensitive ion channels or create pores in the cellular outer membrane, allowing an influx of typically plasma-membrane-impermeant ions. Studies using fluorescent intensity-based calcium ion (Ca 2þ ) sensitive dyes show changes in Ca 2þ levels after various IR stimulation parameters, which suggests that Ca 2þ may originate from the external solution. However, activation of intracellular signaling pathways has also been demonstrated, indicating a more complex mechanism of increasing intracellular Ca 2þ concentration. We quantified the Ca 2þ mobilization in terms of influx from the external solution and efflux from intracellular organelles using Fura-2 and a high-speed ratiometric imaging system that rapidly alternates the dye excitation wavelengths. Using nonexcitable Chinese hamster ovarian (CHO-hM 1 ) cells and neuroblastomaglioma (NG108) cells, we demonstrate that intracellular IP 3 receptors play an important role in the IR-induced Ca 2þ , with the Ca 2þ response augmented by ryanodine receptors in excitable cells.

Stimulation of water and calcium dynamics in astrocytes with pulsed infrared light

“…These observations align with the response to infrared stimulation seen in neuroblastoma‐glioma and hippocampal neurons in vitro 40,41 . Pharmacology implicates IP 3 R as a primary pathway for the release of [Ca 2+ ] i from intracellular stores and is believed to be critical in numerous astrocytic functions 1,2 .…”

IP3-Mediated Calcium Signaling Is Involved in the Mechanism of Fractalkine-Induced Hyperalgesia Response

“…Fractalkine has been shown to lead to increased cytosolic calcium in microglia [21]. Moreover, calcium antagonists are effective pain treatments [22]. In the present study, our results showed that [Ca 2+ ] i significantly increased after incubation with fractalkine in calcium-containing and calcium-free media, and this effect was dose-dependent.…”

Two-photon GCaMP6f imaging of infrared neural stimulation evoked calcium signals in mouse cortical neurons in vivo

“…Plasma membrane nanoporation has also been proposed 16 . Intracellular effects have also been demonstrated, particularly an increase of intracellular calcium ion concentration, originating from mitochondrial stores in cardiac cells 17 or from the endoplasmic reticulum, via activation of the phospholipase C and the inositol trisphosphate (IP 3 ) signaling pathway in neural and glial cells 18 , chinese hamster ovary cells, neuroblastoma-glioma cells 19 , and in cultured spiral ganglion neurons 20 . More recently, the role of the fast activation of voltage-dependent potassium ion channels in unmyelinated axons in the frame of infrared inhibition has been suggested in both modeling and experimental studies 21 , 22 .…”