RT Journal Article
SR Electronic
T1 Determination of Transmembrane Water Fluxes in Neurons Elicited by Glutamate Ionotropic Receptors and by the Cotransporters KCC2 and NKCC1: A Digital Holographic Microscopy Study
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 11846
OP 11854
DO 10.1523/JNEUROSCI.0286-11.2011
VO 31
IS 33
A1 Pascal Jourdain
A1 Nicolas Pavillon
A1 Corinne Moratal
A1 Daniel Boss
A1 Benjamin Rappaz
A1 Christian Depeursinge
A1 Pierre Marquet
A1 Pierre J. Magistretti
YR 2011
UL http://www.jneurosci.org/content/31/33/11846.abstract
AB Digital holographic microscopy (DHM) is a noninvasive optical imaging technique that provides quantitative phase images of living cells. In a recent study, we showed that the quantitative monitoring of the phase signal by DHM was a simple label-free method to study the effects of glutamate on neuronal optical responses (Pavillon et al., 2010). Here, we refine these observations and show that glutamate produces the following three distinct optical responses in mouse primary cortical neurons in culture, predominantly mediated by NMDA receptors: biphasic, reversible decrease (RD) and irreversible decrease (ID) responses. The shape and amplitude of the optical signal were not associated with a particular cellular phenotype but reflected the physiopathological status of neurons linked to the degree of NMDA activity. Thus, the biphasic, RD, and ID responses indicated, respectively, a low-level, a high-level, and an “excitotoxic” level of NMDA activation. Moreover, furosemide and bumetanide, two inhibitors of sodium-coupled and/or potassium-coupled chloride movement strongly modified the phase shift, suggesting an involvement of two neuronal cotransporters, NKCC1 (Na-K-Cl) and KCC2 (K-Cl) in the genesis of the optical signal. This observation is of particular interest since it shows that DHM is the first imaging technique able to monitor dynamically and in situ the activity of these cotransporters during physiological and/or pathological neuronal conditions.