engleski

Densities of Serotonergic Projections as Revealed by In Situ Synthesised Labelled alpha-Methyl-Serotonin : an Autoradiographic Evaluation

An estimate of serotonergic innervation density and regional serotonin (5-HT) concentration was performed from the distribution of in situ produced labelled alpha-methyl-serotonin. Rats were injected with ((3)H) labelled alpha-methyl-l-tryptophan and the tracer distribution was measured using the autoradiographic method 14 days following the injection. In a separate experiment, the total brain concentration of 5-HT in the rat brain was found to be 2.4 +/- A 0.2 nmol/g. Based on this, and the assumption that the specific activity of in situ produced alpha-methyl-serotonin is the same as that of the injected tracer, it was possible to estimate the regional concentrations of 5-HT and the relative concentration of regional serotonergic innervations. It was found, and reported for the first time here, that the highest concentration of serotonergic innervation is present in the solitary nucleus. Regionally measured 5-HT concentrations accord well with previously reported concentrations of 5-HT.

dorsal raphe nucleus; rat-brain; ascending projections; synthesis invivo; tryptophan; hydroxylase; forebrain; terminals; neurons; system

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