Real Time Imaging and Dynamics of Hippocampal Zn2+ under Epileptic Condition Using a Ratiometric Fluorescent Probe

Abstract

Zinc, the essential trace element in human body exists either in the bound or free state, for both structural and functional roles. Insights on Zn2+ distribution and its dynamics are essential in view of the fact that Zn2+ dyshomeostasis is a risk factor for epileptic seizures, Alzheimer’s disease, depression, etc. Herein, a bipyridine bridged bispyrrole (BP) probe is used for ratiometric imaging and quantification of Zn2+ in hippocampal slices. The green fluorescence emission of BP shifts towards red in the presence of Zn2+. The probe is used to detect and quantify the exogenous and endogenous Zn2+ in glioma cells and hippocampal slices. The dynamics of chelatable zinc ions during epileptic condition is studied in the hippocampal neurons, in vitro wherein the translocation of Zn2+ from presynaptic to postsynaptic neuronal bodies is imaged and ratiometrically quantified. Raman mapping technique is used to confirm the dynamics of Zn2+ under epileptic condition. Finally, the Zn2+ distribution was imaged in vivo in epileptic rats and the total Zn2+ in rat brain was quantified. The results favour the use of BP as an excellent Zn2+ imaging probe in biological system to understand the zinc associated diseases and their management.