Nanosecond UV lasers stimulate transient Ca²⁺ elevations in human hNT astrocytes.

Abstract

Astrocytes respond to various stimuli resulting in intracellular Ca²⁺ signals that can propagate through organized functional networks. Recent literature calls for the development of techniques that can stimulate astrocytes in a fast and highly localized manner to emulate more closely the characteristics of astrocytic Ca²⁺ signals in vivo. In this article we demonstrate, for the first time, how nanosecond UV lasers are capable of reproducibly stimulating Ca²⁺ transients in human hNT astrocytes. We report that laser pulses with a beam energy of 4-29 µJ generate transient increases in cytosolic Ca²⁺. These Ca²⁺ transients then propagate to adjacent astrocytes as intercellular Ca²⁺ waves. We propose that nanosecond laser stimulation provides a valuable tool for enabling the study of Ca²⁺ dynamics in human astrocytes at both a single cell and network level. Compared to previously developed techniques nanosecond laser stimulation has the advantage of not requiring loading of photo-caged or -sensitising agents, is non-contact, enables stimulation with a high spatiotemporal resolution and is comparatively cost effective.