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Showing papers by "Anders Björklund published in 1968"


Journal ArticleDOI
TL;DR: Fluorophores induced from noradrenaline and dopamine in tissue sections by treatment with formaldehyde can be separated by their different behavior upon HCl treatment by using a microspectrofluorometer.
Abstract: Fluorophores induced from noradrenaline and dopamine in tissue sections by treatment with formaldehyde can be separated by their different behavior upon HCl treatment. The noradrenaline fluorophore converts to a fully aromatic isoquinoline while the dopamine fluorophore remains in the form of a nonquinoidal dihydroisoquinoline. The two fluorophores have readly distinguishable excitation spectra. The procedure has been tested both in model systems and in tissue sections. The microspectrofluorometer used is described.

203 citations


Journal ArticleDOI
TL;DR: An accumulation of monoamines is found in the adult eminentia mediana and infundibular stem, close to the capillaries of the primary plexus, where they seem to be stored mainly in closely packed delicate varicose fibres, often with swollen endings, “droplets”.
Abstract: An accumulation of monoamines is found in the adult eminentia mediana and infundibular stem, close to the capillaries of the primary plexus, where they seem to be stored mainly in closely packed delicate varicose fibres, often with swollen endings, “droplets”. The first traces of monoamines are visible in the embryonic eminentia of fetuses from the last three days of the gestation period, but typical monoamine-containing fibre endings close to the primary plexus capillaries in zona externa are not found until towards the end of the first post-natal week. The adult condition is attained two weeks later. Nearly all cells in the adult pars intermedia show a specific yellowish fluorescence whose intensity shows a wide individual variation. Such fluorescent cells are sometimes present in the intermedia of the new-born. In some but not all adult specimens, a fluorescent varicose fibre system is visible. Fluorescent fibres were first observed in the intermedia of the new-born. Fluorescent fibres are visible in n. arcuatus and n. paraventricularis in the fetus at the 16th day of the gestation period. Nerve cell bodies storing visible amounts of monoamines are found in n. arcuatus, n. periventricularis anterior, and n. premammillaris ventralis of the adult. This amine storing activity is first visible in n. arcuatus of the embryo at the 17th day of the gestation period. The adult condition of these cells is reached during the first postnatal week.

108 citations


Journal ArticleDOI
TL;DR: A combination of fluorescence microscopy and aldehyde-fuchsin staining on the same sections demonstrated that the majority at least of these monoamine-containing structures were not identical with alde enzyme positive neurosecretory fibres.
Abstract: A rich system of monoamine-containing fibres is described in the neural lobe and pars intermedia of the pig and rat. a) A rich network of delicate varicose fibres is evenly distributed throughout the parenchyma of the neural lobe and surrounds the cells of the pars intermedia. b) Droplets or clusters of droplets are scattered throughout the neural lobe. Most of them probably constitute terminal swellings or end-apparatuses of smooth or varicose fibres. The number of droplets varies from animal to animal; they are found also in the pars intermedia. c) Coarse varicose fibres are mainly localized around larger vessels. At least some of these fibres are nerve fibres of sympathetic origin. A combination of fluorescence microscopy and aldehyde-fuchsin staining on the same sections demonstrated that the majority at least of these monoamine-containing structures were not identical with aldehyde-fuchsin positive neurosecretory fibres.

103 citations


Journal ArticleDOI
TL;DR: The combined formaldehyde-ozone reaction and the acidification after the formaldehyde reaction have been successfully applied to tissues incubated with tryptamine, and they provide sensitive and almost selective methods for the detection of tryptamines at the cellular level.
Abstract: Summary A sensitive histochemical fluorescence procedure for the demonstration of tryptamine by a formaldehyde condensation reaction has been devised. This gives a 13–18 fold increase in the fluorescence yield of tryptamine compared with the conventional Falck-Hillarp method. The conditions of the conventional formaldehyde condensation reaction were modified in the following two ways: 1. A gaseous oxidant (ozone) was introduced into the reaction vessel. Up to a certain concentration of ozone, the yield of the formaldehyde-induced tryptamine fluorescence was markedly increased, probably because of an increased oxidative dehydrogenation of the initial condensation product. None of the other compounds tested showed such an increase in the fluorescence yield upon the combined formaldehyde-ozone procedure. In fact, the fluorescence yields of catecholamines and 5-HT were reduced to about 20 % compared with the yields in the conventional formaldehyde treatment. This decrease in the fluorescence intensity was presumably caused by an oxidative break-down of the amines or of their fluorophores. 2. The amine models were acidified by means of HC1-vapour or glacial acetic acid after the conventional formaldehyde treatment, causing a marked increase in the fluorescence yield of tryptamine. The microspectrofluorimetric characteristics of the fluorophores of different indole compounds (tryptamine, N-methyl tryptamine, 5-HT, and tryptophan) where studied at various pH both after conventional formaldehyde treatment and after combined formaldehyde-ozone treatment. The behaviour of the tryptamine fluorophore under various conditions was characteristic and differed from that of the other indoles and catechols tested, which makes possible the microspectrofluorimetric identification of tissue tryptamine. The combined formaldehyde-ozone reaction and the acidification after the formaldehyde reaction have been successfully applied to tissues incubated with tryptamine, and they provide sensitive and almost selective methods for the detection of tryptamine at the cellular level.

73 citations


Journal ArticleDOI
TL;DR: A modified histochemical procedure is described, which reduces to a minimum the exposure of the specimens to hot paraffin and xylene, and with this procedure, a higher sensitivity and reproductiveness of the fluorescence method is achieved in many structures, e.g., in the mammalian pituitary gland.
Abstract: The fluorophores formed from catecholamines in certain fiber structures are easily extracted from their tissue sites by xylene or hot paraffin, in contrast to the fluorophores in the ordinary adrenergic nerve fibers, which are fairly resistant to such media. A modified histochemical procedure is described, which reduces to a minimum the exposure of the specimens to hot paraffin and xylene. With this procedure, a higher sensitivity and reproductiveness of the fluorescence method is achieved in many structures. Thus hitherto unknown monoamine-containing structures have been detected, e.g., in the mammalian pituitary gland.

57 citations


Journal ArticleDOI
TL;DR: None — or only little — of the catecholamines and 5-HT but some other monoamine-like substance is stored in the fluorescent cells of the adenohypophysis, preliminary studies suggest.
Abstract: In the pituitary gland of the cat, dopamine (M.V. 0.78 μg/g), noradrenaline (M.V. 0.29 μg/g) and 5-HT (M.V. 0.94 μg/g) have been found. With the histochemical fluorescence method, a rich system of delicate fluorescent varicose fibres, often provided with irregular swellings or droplets, was observed in the neural lobe and pars intermedia. Microspectrofluorimetrically, these fibre structures exhibit the spectral characteristics of catecholamines. Most cells in the pars intermedia and a large number of cells in pars distalis show a yellowish fluorescence, with microspectrofluorimetric characteristics which differ entirely from those of the catecholamines and 5-HT. In animals treated with reserpine, the pituitary dopamine, noradrenaline, and 5-HT are largely depleted. However, the intensity and the spectral properties of the cellular fluorescence are not affected by this treatment, whereas the fluorescent fibres can no longer be seen. Thus none — or only little — of the catecholamines and 5-HT but some other monoamine-like substance is stored in the fluorescent cells of the adenohypophysis. Preliminary studies suggest that this substance is closely related to or perhaps identical with tryptamine.

56 citations


Journal ArticleDOI
TL;DR: The occurrence of monoamines in the median eminence of the untreated pigeon, chick, goose, sparrow, and gull was studied in this article, and it was found that 1-dopa, dopamine, noradrenaline, and 5-hydroxytryptamine were accumulated into the fibers of the zona externa.
Abstract: 1. The occurrence of monoamines in the median eminence of the untreated pigeon, chick, goose, sparrow, and gull was studied. In all species, monoamines were found in the external layer localized in delicate varicose fibres. It was also found that the fluorescence intensity in the external layer of the median eminence clearly differed in various species, the pigeon having the weakest fluorescence and the chick the strongest. 2. The uptake of exogenous amines in the zona externa of the median eminence was investigated in the pigeon and the chick. The following substances, 1-dopa, dopamine, noradrenaline, and 5-hydroxytryptamine were accumulated into the fibers of the zona externa. A species difference could be ascertained; in general, chicks tolerated higher doses of amines than did pigeons. 3. In contrast to mammals, it was established that cocaine failed to prevent the accumulation of 1-dopa, dopamine, and α-methyl-noradrenaline in the zona externa of both pigeons and chicks.

34 citations