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R Massarelli

Publications and source records attributed to R Massarelli.

At least 91 records · Page 5Linked to original sources

Cholinesterase activity and choline uptake in intact nerve cell cultures.

Choline uptake and ecto-cholinesterase activities have been measured in intact astroblast and neuroblast cultures. The data show that choline uptake is dependent upon the ionic composition of the culture medium and is sensitive to metabolic inhibitors. However, the high concentrations of the inhibitors necessary for the inhibition of the uptake and some thermodynamic properties qould suggest a facilitated transport rather than an active uphill process. Preincubation of the cultures with various inhibitors of cholinesterases shows no direct parallelism between inhibition of choline high affinity uptake (apparent Km approximately equal to 10-6 M) and inhibition of ecto-acetylcholinesterase (EC 3.1.1.7).

Animals↗

Acetylcholine concentrations in rat brain: diurnal oscillation.

A diurnal oscillation of acetylcholine concentrations in rat brain has been demonstrated by gas chromatography. Peak concentrations occur at 2 hours of light, and a trough is seen at 6 hours of darkness. This pattern is observed only in grouped rats, and emerges after at least 18 days of prior conditioning in an environment with controlled light, humidity, and temperature.

Acetates↗

In vitro and in vivo ethanolamine metabolism in rat brain: effect of time and aging.

The effect of the time in culture of foetal rat neurons and age on the incorporation of radioactive ethanolamine into methylated derivatives was investigated. Decreased incorporation of [3H]ethanolamine into its various methylated water-soluble and lipidic derivatives was observed in rat neurons cultures at 12 day in vitro (DIV) as compared to the 3rd and the 7th DIV. In vivo studies showed that there was a diminished labeling of methylated products in the older animals as compared to the younger ones. These in vitro and in vivo observations suggest a generalized decrease of N-methyltransferase activities during maturation and aging.

Aging↗