Pulsed infrared radiation: a potential tool to reveal cellular secrets: Pulsed infrared radiation (IR) has been shown to stimulate excitable cells through activating key intracellular signalling events. Data suggest the presence of fundamental IR-sensitive mechanisms that generalize across cell types. Our recent results demonstrate the importance of IR-modulated intracellular Ca2+ signalling in cardiomyocytes and inner-ear hair cells. Application of pulsed IR to modulate intracellular Ca2+ may be particularly useful to study events controlling synaptic transmission