A series of iminocoumarin-based fluorescent Ca2+ indicators were synthesized and the spectral profiles of their free and Ca2+ bound forms were studied. The newly-synthesized compounds incorporate the Ca2+ chelating structure of BAPTA. The chromophore moieties are iminocoumarins substituted at the 3-position with benzothiazolyl, benzoxazolyl and benzimidazolyl groups. These compounds are excited with visible light and their Ca2+ dissociation constants range from 5.4 to 27.5 microM. Fluorescence spectra studies of these probes indicated a clear shift in their excitation wavelength maxima upon Ca2+ binding along with changes in fluorescence intensity that enable the compounds to be used as low Ca2+ affinity, visible excitable probes.
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http://dx.doi.org/10.1054/ceca.2001.0240 | DOI Listing |
Proc Natl Acad Sci U S A
February 2025
SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea.
The design of organic-peptide hybrids has the potential to combine our vast knowledge of protein design with small molecule engineering to create hybrid structures with complex functions. Here, we describe the computational design of a photoswitchable Ca-binding organic-peptide hybrid. The designed molecule, designated Ca-binding switch (CaBS), combines an EF-hand motif from classical Ca-binding proteins such as calmodulin with a photoswitchable group that can be reversibly isomerized between a spiropyran (SP) and merocyanine (MC) state in response to different wavelengths of light.
View Article and Find Full Text PDFInt J Nanomedicine
January 2025
Department of Biopharmacy, School of Pharmaceutical Sciences, Jilin University, Changchun, People's Republic of China.
Pflugers Arch
January 2025
Division of Neurophysiology, Department of Physiology, Hyogo Medical University, Hyogo, 663 8501, Japan.
The nucleus tractus solitarius (NTS) contains neurons that relay sensory swallowing commands information from the oropharyngeal cavity and swallowing premotor neurons of the dorsal swallowing group (DSG). However, the spatio-temporal dynamics of the interplay between the sensory relay and the DSG is not well understood. Here, we employed fluorescence imaging after microinjection of the calcium indicator into the NTS in an arterially perfused brainstem preparation of rat (n = 8) to investigate neuronal population activity in the NTS in response to superior laryngeal nerve (SLN) stimulation.
View Article and Find Full Text PDFJ Integr Neurosci
January 2025
Neuroscience Department, University of Connecticut Health, School of Medicine, Institute for Systems Genomics, Farmington, CT 06030, USA.
Background: In neuroscience, Ca imaging is a prevalent technique used to infer neuronal electrical activity, often relying on optical signals recorded at low sampling rates (3 to 30 Hz) across multiple neurons simultaneously. This study investigated whether increasing the sampling rate preserves critical information that may be missed at slower acquisition speeds.
Methods: Primary neuronal cultures were prepared from the cortex of newborn pups.
Exp Eye Res
January 2025
Department of Basic and Translational Science, Philadelphia, PA, 19104, United States; Department of Physiology, Philadelphia, PA, 19104, United States. Electronic address:
The P2X7 receptor (P2X7R) for extracellular ATP is implicated in several forms of retinal degeneration, including diabetic retinopathy, age-related macular degeneration, and glaucoma. P2X7R stimulation can trigger release of master cytokine IL-1β from microglia in the brain and from macrophages, but evidence of release from retinal microglia is indirect. Isolated mouse and rat retinal microglia, and wholemounts from CX3CR1 mice, were examined to determine if ATP induced IL-1β release directly from retinal microglial cells and if it also primed expression of IL-1β on an mRNA and protein level.
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