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P Einarsson

Publications and source records attributed to P Einarsson.

5 recordsLinked to original sources
PubMed1975

Microspectrofluorimetric analysis of the formaldehyde induced fluorescence in midbrain raphe neurons.

The formaldehyde induced fluorescence in perikarya localized in the midbrain rephe nuclei was investigated using the Falck-Hillarp technique in combination with qualitative (spectral analysis) and quantitative microspectorfluorimetry. The spectral evidence obtained after various pharmacological and lesion experiments with the neurotoxic compounds 5,6-dihydroxytryptamine and 5,7-dihydroxytryptamine, strongly favours the view that the vast majority of the perikarya in the cell groups B-7, B-8 and B-9 (according to Dahlström and Fuxe) are 5-hydroxytryptamine neurons, defined as structures capable of synthesizing, metabolizing, and storing 5-hydroxytryptamine. The spectral data indicate that the 5-hydroxytryptamine neurons might contain in addition to 5-hydroxytryptamine another indolealkylamine, possibly tryptamine, in low concentrations. The perikarya were shown to be able to take up and accumulate exogenously administered 6-hydroxytryptamine provided that monoamine oxidase was inhibited. Quantitative microfluorimetric analysis disclosed that the tryptophan hydroxylase inhibitor p-chlorophenylalanine was unable to block effectively this enzyme in the 5-hydroxytryptamine perikarya, although acutely a partial blockade was observed. The 5-hydroxytryptamineerogenously to the action of p-chlorophenylalanine and this might be associated with different states of neuronal activity. The difference in potency of p-chlorophenylalanine as regards tryptophan hydroxylase inhibition in perikarya and in nerve terminals may be related to different properties of tryptophan hydroxylase in various parts of the neuron and/or to a high turnover of the enzyme in the perikarya.

5-Hydroxytryptophan↗
PubMed1975

Quantitative microfluorimetry of formaldehyde induced fluorescence of dopamine in the caudate nucleus.

Quantitative microfluorimetric studies were carried out on the formaldehyde induced fluorescence of dopamine in nerve terminals of the nuc. caudatus putamen using the technique of Falck and Hillarp. After tyrosine hydroxylase inhibition produced by alpha-methyl-p-tyrosine (H 44/68) a time-dependent disappearance of the dopamine fluorescence occurred in an exponential manner, T1/22.6 hr. Apomorphine treatment resulted in a considerable counteraction of the H 44/68 induced reduction of the fluorescence, whereas treatment with haloperidol potentiated it. Administration of gamma-hydroxybutyrolactone led to a marked increase of the dopamine fluorescene. The present microfluorimetric results were in perfect agreement with chemical-analytical determinations of dopamine carried out under identical experimental conditions, and with those reported previously. The fluorescence intensities obtained in the nuc. caudatus putamen were found to be in the linear part of the dopamine fluorescence concentration relationship as observed in protein models. It may be concluded that by using microfluorimetric quantitation of the formaldehyde induced fluorescence in the nuc. caudatus putamen it is possible to obtain a reliable quantitation of the relative amount of dopamine in the dopamine nerve terminals.

Animals↗