Calcium Wave Of Astrocytes Induced By Femtosecond Pulsed Laser

The present studies show that astrocytes may response to various stimuli with calcium signal,which is a bridge for communication among astrocytes or with other cells. These results suggest that astrocytes participate in the functional activity of the central nervous system. However, the mechanism and function of the calcium signal are not clear. That the method is scatheless, strength-controlled, without the requirement for additional reagent has not been found is one of the reasons.In this paper, the calcium elevation and subsequent wave of astrocytes are induced by the femtosecond pulsed laser. There are two different patterns of calcium elevation induced by different intensity of the laser: spike-type (S-type) and higher and/or sustained-type (H-type) extracellular calcium-dependent of calcium elevation after stimulus confirmed that photoporation is the reason of calcium elevation induced by femtosecond pulsed laser.The calcium elevation induced by photoporation can spread around the other astrocytes. The radius of calcium wave induced by S-type and H-type calcium elevation is 80.2±7.3μm and 176.6±12.1μm, respectively. Pharmacological evidences have confirmed that extracellular ATP through P2Y receptor is the mechanism of calcium wave.The calcium wave induced by H-type calcium elevation can induce the synchronous transient rises of calcium in neurons, and nor the calcium wave induced by S-type calcium elevation. This suggests that different degrees of activity in astrocytes modulate different responses of neurons.These results suggest that photoporation induced by femtosecond pulsed laser could result in the calcium elevation and wave of astrocytes. The photic stimulus has the advantages including scatheless, strength-controlled, unchanged intracellular or extracellular environment of astrocytes and etc. It is a new method to induce the calcium signal of astrocytes.