Evaluation of Fluorescent Cu2+ Probes: Instant Sensing, Cell Permeable Recognition and Quantitative Detection

By incorporating a rhodamine spirolactam structure as the recognition site for Cu2+, two novel probes were synthesized through a connection of rhodamine 6G acylhydrazine and 5-formyl-6-hydroxyl-4-methylcoumarin/2,4-dihydroxybenzaldehyde. In the recognition process of probes towards Cu2+, the spirolactam ring exhibited opening and closing, accompanying an instant and specific change in fluorescence and in color, which could also achieve a naked-eye and semiquantitative recognition of aqueous Cu2+ besides the fluorescent Cu2+ detection method. Fluorescent analyses and ECV304 cell imaging further revealed the probes’ good optical stability, instant response, low toxicity, and membrane permeability, which offers future possibilities for the probes’ instant detection and the real-time tracking of Cu2+ in biological systems.

Regulation of [Ca2+]c oscillations by plasma membrane Ca2+ fluxes: a role for natriuretic peptides

We have investigated the effects of natriuretic peptides on oscillations in [Ca2+]c (cytosolic free Ca2+ concentration) in two different cell types: freshly isolated rat hepatocytes and the ECV304 cell line. Our data, from both cell types, suggest that natriuretic peptides modulate the frequency of [Ca2+]c oscillations through alterations in plasma membrane Ca2+ fluxes. Here, we review evidence for a role for plasma membrane Ca2+ fluxes in the control of the frequency of [Ca2+]c oscillations. We describe a hypothetical mechanism through which this might be achieved. We propose a physiological role for regulated control of Ca2+ efflux in modulating [Ca2+]c oscillations.