Authors

Mironov, S L

Affiliations

DFG-Centre of Molecular Physiology of the Brain, Department of Neuro- and Sensory Physiology, Georg-August-University, Gottingen, Germany.

Application Area

Cell Biology

Calcium Imaging

Abstract

The exchange factor directly activated by cAMP (Epac) can couple cAMP production to the activation of particular membrane and cytoplasmic targets. Using patch-clamp recordings and calcium imaging in organotypic brainstem slices, we examined the role of Epac in pre-Bötzinger complex, an essential part of the respiratory network. The selective agonist 8-(4-chlorophenylthio)-2'-O-methyl-cAMP (8-pCPT) sensitized calcium mobilisation from inositol-1,4,5-trisphosphate-sensitive internal stores that stimulated TRPM4 (transient receptor potential cation channel, subfamily M, Melastatin) channels and potentiated the bursts of action potentials. 8-pCPT actions were abolished after inhibition of phospholipase C with U73122 and depletion of calcium stores with thapsigargin. Caffeine-sensitive release channels were not modulated by 8-pCPT. Epac inhibited ATP-sensitive K(+) channels that also led to the enhancement of bursting by 8-pCPT. Bursting activity, spontaneous calcium transients and activity of TRPM4 and ATP-sensitive K(+) channels were potentiated after brief exposures to bradykinin and incubation with wortmannin produced opposite effects that can be explained by changes in phosphatidylinositol 4,5-bisphosphate levels. 8-pCPT stimulated the respiratory motor output in functionally intact preparations and the effects of bradykinin and wortmannin were identical to those observed in organotypic slices. The data thus indicate a novel pathway of controlling bursting activity in pre-Bötzinger complex neurons through Epac that can be involved in reinforcement of the respiratory activity by cAMP.

Extract

… “the slices in experiments were placed in a chamber mounted on an upright microscope (Axioscope 2, Carl Zeiss AG, Gottingen, Germany) and visualized with a 40• objective. The excitation light (425 nm) from CoolLED (BFI Optilas, Puchheim, Germany)”…

Product Associated Features

pE-100: A range of compact, simple-to-use, single wavelength illumination systems for screening fluorescence.

Diascopic Technique

-

Live Cell Issues

-

Product Type

pE-100

Journal

The Journal of Physiology

Year of Publication

2013

Country of Publication

Germany