Acetylcholine secretion enhanced by glutamate in rat embryonic spinal motoneurons: respective involvement of NMDA and AMPA receptors.

The spontaneous acetylcholine secretion and endogenous acetylcholine content were measured by means of chemiluminescent assay from isolated embryonic rat spinal motoneurons. The sensitivity of the detection allows to study the kinetics of the acetylcholine secretion with short time intervals. Following the demonstration of the presence of acetylcholine and glutamate in embryonic motoneurons, the aim of this work was to study the characteristics of acetylcholine secretion and the effect of glutamate in its modulation.

Predicted acetylcholine layer around embryonic motoneurones.

The secretion of acetylcholine (ACh) from cultures of dissociated rat purified embryonic motoneurones into the medium was measured at different times using a chemiluminescent assay. From these results it is proposed that a motoneurone is able to generate an extracellular ACh layer surrounding its membrane. This layer is expected to modulate the ACh concentration at the membrane in a range where ACh receptors can be sensitive, and thus to affect the response of the motoneurone.

Synthesis and release of an acetylcholine-like compound by human myoblasts and myotubes.

1. Exogenously applied acetylcholine (ACh) is a modulator of human myoblast fusion. Using a chemiluminescent method, we examined whether an endogenous ACh-like compound (ACh-lc) was present in, and released by, pure human myogenic cells.

Enhanced chemiluminescent assays for acetylcholine.

Acetylcholine and choline chemiluminescent assays have limitations when these compounds are detected in small areas of mammalian nervous tissue. Use of 7-dimethyl-aminonaphthalene-1,2-dicarbonic acid hydrazide (7-DMAN), instead of luminol, gives a threefold increase in emitted light in the chemiluminescent assay for acetylcholine based on the coupled choline oxidase-peroxidase reaction. Addition of light enhancers, such as para-iodophenol or D-luciferin, to luminol or 7-DMAN further increased the light emission.

High-sensitive chemiluminescent assay for cholesterol.

Chemiluminescent measurement of cholesterol can be performed in various biological tissues and fluids. The method described in this study has a sensitivity of 54 pmol. The tissue samples used for the determination of cholesterol can be reduced to as little as 1 mg and assay can be performed on diluted biological fluids, allowing sampling of plasma or serum as little as 5 microliters.