Effects of Low-Level Laser Exposure on Calcium Channels and Intracellular Release in Cultured Astrocytes

摘要

Prompted by a study of traumatic brain injury (TBI) in a model system of cultured astrocytes, we discovered that low level laser illumination (LLL) at 660nm elevates the level of intracellular Ca~(2+). The coherence of the illumination was not essential since incoherent red light also worked. For cells bathed in low Ca~(2+) saline so that influx was suppressed, the Ca~(2+) level rose with no significant latency following illumination and consistent with a slow leak of Ca~(2+) from storage such as from the endoplasmic reticulum and/or mitochondria. When the cells were bathed in normal Ca~(2+) saline, the internal Ca~(2+) rose, but with a latency of about 17 seconds from the beginning of illumination. Pharmacologic studies with ryanodine inhibited the light effect. Testing the cells with fluid shear stress as used in the TBI model showed that mechanically induced elevation of cell Ca~(2+) was unaffected by illumination.