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Showing papers by "Anders Björklund published in 1972"


Journal ArticleDOI
17 Mar 1972-Science
TL;DR: The growth of new axonal sprouts was studied from transected, ascending noradrenergic axons into transplants of iris tissue in the caudal hypothalamus of the rat and the effect seemed to be proportional to the administered dose of nerve growth factor.
Abstract: The growth of new axonal sprouts was studied from transected, ascending noradrenergic axons into transplants of iris tissue in the caudal hypothalamus of the rat. A single intraventricular injection of nerve growth factor, given at the time of axonal damage, resulted in an increased formation and growth of new noradrenaline sprouts 7 days later. The effect seemed to be proportional to the administered dose of nerve growth factor.

148 citations


Journal ArticleDOI
TL;DR: It is shown that the yield of fluorophores is considerably higher in the glyoxylic acid vapours reaction than in the formaldehyde vapour reaction of the standard Falck-Hillarp method, and that this higher efficiency is due to the most favourable catalysing properties of the carboxylic group of the gly oxygenlic acid molecule.
Abstract: Glyoxylic acid vapour is a most powerful reagent for the fluorescence histochemical visualization of biogenic monoamines. In the present investigation the mechanisms of fluorophore formation in the glyoxylic acid reaction has been studied in detail for tryptamine in histochemical models and in freeze-dried tissue, utilizing microspectrofluorometric, Chromatographic, and mass spectrometric techniques in combination with isotope measurements.

126 citations


Journal ArticleDOI
TL;DR: The occurrence of a rich, peripheral sympathetic innervation in the medial habenular nucleus of the brain offers possibilities for a previously not observed sympathetic influence on this nucleus.
Abstract: The pineal gland of the rat is located near the brain surface and is via a slender stalk connected to lamina intercalaris which constitutes a cell formation between the habenular and posterior commissures, continuing to the subcommissural organ. The stalk and lamina intercalaris, like the pineal proper, exhibited a yellow, formaldehyde-induced fluorescence which showed the histochemical and pharmacological properties of 5-HT. All these structures were richly supplied with catecholamine-fluorescent nerves which could be further followed rostrally from lamina intercalaris, mixing with the non-fluorescent commissural fibres and stria terminalis, into the medial habenular nucleus in which they extensively supplied both blood vessels and non-fluorescent nerve cells. Cytospectrofluorometric and chemical analysis suggested that the fluorescent nerves stored noradrenaline. This was supported by the finding that they disappeared after bilateral cervical sympathectomy (as did the fluorescent nerves in the pineal complex). In the medial habenular nucleus also catecholamine-containing and 5-HT-containing nerves of central origin were present. The occurrence of a rich, peripheral sympathetic innervation in the medial habenular nucleus of the brain offers possibilities for a previously not observed sympathetic influence on this nucleus. Also the arrangement, and the apparent continuity of the sympathetic innervation in the pineal gland, the lamina intercalaris, and the medial habenular nucleus, suggests some functional interconnection or coordination between these structures.

111 citations


Journal ArticleDOI
TL;DR: Results indicate that within a proper dose range the 5,6-DHT-induced degeneration is largely restricted to indolamine axons and axon terminals, and unselective effects on other unmyelinated axons, on myelin, and on glial cells were observed in narrow subependymal zones close to the lateral ventricles.
Abstract: Evidence has been obtained by electron microscopy of a direct cytotoxic effect of intraventricularly administered 5,6-dihydroxytryptamine (5,6-DHT) on unmyelinated axons in the rat brain. Ultrastructural signs of axonal damage were observed in areas rich in indolamine nerve terminals as early as 2 hrs after injection. By 6–24 hrs, characteristic and more dramatic signs of degeneration developed, involving coalescence of all axonal constituents—often in combination with a uniform osmiophilic impregnation of the axoplasm—accompanied by engulfment of the dystrophic structures by glial processes. During the next five days, the degenerating axons and axon terminals appeared to be removed by glial cell phagocytosis, whose equivalents were the inclusion of axonal residues into membrane-bound lysosome-like bodies. Concomitantly, there was a progressively increasing number of extremely large and dilated axons in all regions analysed. These axonal swellings, which have an ultramorphology similar to that of dilated stumps of mechanically severed monoamine axons, correspond most probably to proximal, dilated portions of drug-damaged axons.

87 citations


Journal ArticleDOI
TL;DR: The alteration in the appearance of the fluorescent fibers in the dorsal lateral geniculate nucleus after visual cortex ablation is interpreted as an increase in the adrenergic innervation of this nucleus produced by denervation, further evidence of the plasticity of central monoamine neuron systems.

80 citations


Journal ArticleDOI
TL;DR: Results indicate that this characteristic fluorideophore is formed from the noradrenaline fluorophore in a high degree also in tissue sections, when the rising over-all tissue fluorescence makes measurement increasingly difficult.
Abstract: Treatment with HCl induces changes in the excitation spectra of the formaldehyde condensation products of dopamine and noradrenaline that permit the distinction of these two catecholamines on the cellular level. Using histochemical models and tissue sections, these spectral shifts and changes in the ratio of the two main excitation peaks at about 320 and 370 nm have been measured. Acidification of the dopamine fluorophore rapidly leads to the conversion of the quinoidal dihydroisoquinoline fluorophore into its tautomeric nonquinoidal form. The process probably goes to completion within a few seconds following treatment with HCl. The fluorophore remains stable during prolonged acid treatment. The conversion of the noradrenaline fluorophore into its nonquinoidal state is equally rapid; however, the subsequent dehydration to the fully aromatic form is a slower process, and it is apparently not complete even after several minutes, when the rising over-all tissue fluorescence makes measurement increasingly dif...

65 citations


Journal ArticleDOI
TL;DR: Significant visible fluorescence was induced from catecholamines and indolamines with aldehydes, ketones, α-keto acids and carboxylic acids, suggesting that all of these compounds can enter fluorophore-forming cyclization reactions under the histochemical gas phase conditions.
Abstract: The capacity of biogenic amines to form fluorophores in histochemical gas phase reactions has been tested with 20 compounds having a carbonyl group (> C = O) as a common characteristic. Significant visible fluorescence was induced from catecholamines and indolamines with aldehydes, ketones, α-keto acids and carboxylic acids, suggesting that all of these compounds can enter fluorophore-forming cyclization reactions under the histochemical gas phase conditions. The most "reactive" reagents are found among the low molecular aldehydes, and formaldehyde and glyoxylic acid seem to be the most suitable reagents, combining high reactivity with good selectivity. Fluorescence, interesting for the histochemical demonstration of N-acetylated indolamines, was obtained from melatonin and N-acetyl-5-hydroxytryptamine with some acid reagents (glyoxylic acid, formic acid, acetic acid and pyruvic acid). A direct cyclodehydration according to the classical Bischler-Napieralski reaction is the most likely mechanism underlyin...

45 citations


Journal ArticleDOI
TL;DR: Die Histidin-Decarboxylase-(HD)-Aktivität im Hypothalamus des Kaninchens wurde nach Oophorectomie and Thyroidectomie gemessen, anderswo 20 Tage nach kombinierter Oophoren verdoppelt.
Abstract: Die Histidin-Decarboxylase-(HD)-Aktivitat im Hypothalamus des Kaninchens wurde nach Oophorectomie und Thyroidectomie gemessen. Die Resultate zeigten, dass die HD-Aktivitat sich 20 Tage nach der Oophorectomie und der Thyroidectomie verdoppelt. 20 Tage nach kombinierter Oophorectomie und Thyroidectomie stieg die HD-Aktivitat ungefar 4mal, verglichen mit der Aktivitat des Kontrollmatrials. Sham-operierte Kontrollen zeigten keine Veranderungen der HD-Aktivitat im Hypothalamus.

12 citations