Coordination of mitochondrial activity across the rat salivary glands epithelium imaged by intravital two-photon microscopy

Thursday, October 11, 2012 — Poster Session III
10:00 a.m. – Noon	Natcher Conference Center, Building 45	NIDCR	IMAG-24

* FARE Award Winner

Authors

• N. Porat-Shliom
• A. Masedunskas
• R. Weigert

Abstract

In individual cells the levels of the reduced form of nicotinamide adenine dinucleotide (NADH) have been reported to oscillate periodically. To investigate this phenomenon in vivo, we imaged the salivary glands (SGs) of live rats using intravital microscopy, exploiting the fact that NADH emits upon two-photon excitation. Fast scan imaging allowed us to capture periodic oscillations of NADH levels under physiological conditions. Strikingly, we observed that NADH oscillations are temporally and spatially synchronized across the epithelium. Using dyes that are sensitive to mitochondrial membrane potential, such as TMRM, we observed maximal mitochondrial activity in specific areas of the epithelium that propagated throughout the tissue in a wave-like pattern. We hypothesized that the this might be related to the basal secretory activity of the SGs hence we targeted the receptors involved pharmacologically. Inhibition or stimulation of muscarinic, alpha-adrenergic and purinergic receptors did not affect the propagation of the waves, whereas stimulation of beta-adrenergic receptor led to a sharp and uniform increase in fluorescence, and the loss of the oscillations. Based on our findings, we speculated that NADH oscillations and their synchronization might have implications in the coordination of tissue function under physiological conditions.

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