Showing papers by "Anders Björklund published in 1974"

The glyoxylic acid fluorescence histochemical method: a detailed account of the methodology for the visualization of central catecholamine neurons.

Abstract: This paper gives a detailed description of the glyoxylic acid fluorescence histochemical method as designed for the highly sensitive visualization of catecholamine neurons. In this method, the primary catecholamines, dopamine and noradrenaline, are efficiently converted to intensely fluorescent 2-carboxymethyl-dihydroisoquinoline derivatives in a well defined reaction with glyoxylic acid. The method is carried out on sections from fresh or glyoxylic acid-perfused tissue, which are immersed in a glyoxylic acid solution, dried, and then reacted either by heating at +100°C, or by glyoxylic acid vapour treatment at +100°C. The method has a high reproducibility, is rapid and convenient, and if desired, sections of good quality can be ready for fluorescence microscopy within half an hour after the sacrifice of the animal. The glyoxylic acid method demonstrates central and peripheral dopamine- and noradrenaline-containing neurons with an extraordinary sensitivity and precision. The entire adrenergic neuron, including the non-terminal portions of the axon and sometimes also the dendrites, becomes fluorescent, making the method ideal for neuroanatomical tracing of central catecholamine pathways. The spectral characteristics of the glyoxylic acid-induced fluorophores have been investigated, and it is concluded that the catecholamine fluorophores can be identified and distinguished by microspectrofluorometry from those of other fluorogenic monoamines known to occur in the vertebrate brain.

The adrenergic innervation of the rat thalamus as revealed by the glyoxylic acid fluorescence method

Abstract: The adrenergic innervation of the thalamus, epithalamus, metathalamus, and subthalamus in the rat has been investigated by means of the recently introduced glyoxylic acid fluorescence method. Many areas of the thalamus and adjoining regions, that appear sparsely innervated by catecholamine (CA) fibers in specimens processed according to the standard Falck-Hillarp formaldehyde method, were found to be richly supplied with such fibres in the glyoxylic acid-treated specimens. Moreover, the glyoxylic acid method allows the tracing of the CA axons from the cell bodies up to the terminals, and in combination with stereotaxic lesions the following CA systems to the thalamus could be established: 1 The locus coeruleus system. Most of these axons ascend in the so-called dorsal tegmental bundle through the mesencephalon and the zona incerta into the medial forebrain bundle. From this bundle branches were traced along several routes, giving rise to extensive terminal systems in many thalamic, metathalamic and pretectal areas, most notably the anterior, ventral and lateral nuclear complexes, and the medial and lateral geniculate bodies. 2 The dorsal periventricular bundle, which constitutes a previously not described adrenergic component of the dorsal longitudinal fasciculus. This system originates in cell bodies (defined as the A11 cell group) in the dorsal raphe region, the central gray of the mesencephalon, and in the periventricular gray of the caudal thalamus. The axons ascend within the dorsal longitudinal fasciculus and give rise to a thalamic and hypothalamic periventricular system, projecting to medial and midline thalamic, epithalamic and pretectal regions. 3 Part of the terminals in the paraventricular thalamic nucleus was identified with a non-locus projection from cell bodies in the pontine or medullary reticular formation. 4 A system of delicate, probably dopamine-containing axons was revealed in the caudal thalamus, the zona incerta and the dorsal and anterior hypothalamus. This system probably originates in the dopamine cell bodies of the diencephalic A11 and A13 cell groups, forming a hitherto unknown intradiencephalic dopaminergic system. The adrenergic afferent systems to the thalamus can, to a large extent, be regarded as adrenergic components of known ascending reticular projections. The information on the adrenergic systems obtained with the glyoxylic acid method revealed new features of the organization of the thalamic projections from the brain stem reticular formation.

Fluorophore formation from catecholamines and related compounds in the glyoxylic acid fluorescence histochemical method

Abstract: Condensation with glyoxylic acid is a highly sensitive method for fluorescence histochemical demonstration of biogenic monoamines and related compounds. In the present study the fluorophore formation from phenylethylamines in the histochemical glyoxylic acid reaction has been investigated. From an analysis of 32 different phenylethylamine derivatives it was found that strong fluorescence is obtained from 3-hydroxylated and certain 3-methoxylated, primary phenylethylamines, whereas the fluorescence yield from secondary, tertiary, and N-acetylated phenylethylamines is very low.

De- and regeneration of the bulbospinal serotonin neurons in the rat following 5,6-or 5,7-dihydroxytryptamine treatment.

Abstract: In an attempt to determine the conditions which permit central 5-HT neurons to respond to a chemical injury of their axons by sprouting and regeneration, the pattern and time-course of recovery of 5-HT concentrations and regrowth of bulbospinal 5-HT axons were evaluated in rats subjected to intraventricular treatment with either 75 μg 5,6- or 150 μg 5,7-DHT While 5,6-DHT treatment is followed by a significant recovery of 5-HT concentrations in the telodiencephalon, brainstem and upper part of the spinal cord within 3 months, there is no significant restoration of the severely depleted 5-HT levels in the telodiencephalon and spinal cord, and only limited recovery in 5-HT content of the brainstem preparation after 5,7-DHT

Axonal regeneration of peripheral adrenergic neurons: effects of antiserum to nerve growth factor in mouse.

Abstract: The effect of the antiserum to Nerve Growth Factor (NGF) on the regrowth of adrenergic axons following 6-hydroxydopamine-(6-OH-DA)induced axotomy was investigated in the mouse using fluorescence histochemistry and determinations of endogenous NA. A single subcutaneous injection of 0.1 ml/g of anti-NGF serum, given one day after the 6-OH-DA-injection (60 mg/kg), caused a pronounced inhibition of the regeneration of the adrenergic axons in all peripheral tissues investigated (iris, salivary glands, heart, intestine, spleen and pancreas). The ganglionic cell bodies in the superior cervical ganglion underwent a marked atrophy, as observed 5 days and 3 weeks after the 6-OH-DA treatment, but they had regained normal appearance after 2 months. Furthermore, the fluorescence histochemistry revealed an antiserum-induced reduction of the NA content in all parts of the regenerating neurons, except for the most distal portions of the surviving axon stumps. At 5 days and 3 weeks after the 6-OH-DA-treatment the sprouting and regrowth of the adrenergic axons were much reduced in the anti-NGF serum-treated animals. When compared with those of the corresponding controls, the NA levels in the anti-NGF serum-treated specimens were only 20–40% at 3 weeks. The anti-NGF serum-induced inhibition was temporary, and between 3 weeks and 2 months after treatment the regeneration in the antiserum-treated animals started to catch up with the controls. The results indicate that endogenous NGF or NGF-like substances may play a role in the process of regeneration of lesioned sympathetic neurons in the adult animal. They also suggest that mature sympathetic neurons during regeneration resume the high sensitivity to, and dependence on, NGF, which otherwise are characteristic of sympathetic neurons during their ontogenetic growth and development.

Organization of the Dopamine and Noradrenaline Innervations of the Median Eminence-Pituitary Region in the Rat

Abstract: In studies of hypothalamic regulation of pituitary function the interest has mainly been focussed on two classes of substances: the hypothalamic releasing and inhibiting factors (which are peptides) and the biogenic monoamines. There is now much experimental evidence that catecholamines (CA) participate importantly in the regulation of the release of hypothalamic hormones (see Lichtensteiger, 1970; McCann et al., 1972; Hokfelt and Fuxe, 1972; Porter et al., 1972 for reviews) and special attention has been devoted to the role of CAs in the function of the median eminence. This was initiated by the observations by Carlsson et al. (1962) and by Fuxe (1963, 1964) of a massive supply of CA fibres to the median eminence of various mammalian species. In later studies, Fuxe and Hokfelt (1966) and Lichtensteiger and Langemann (1966) provided evidence in the rat and mouse that at least part of this innervation originated in the arcuate nuclei, constituting a tubero-infundibular CA (probably DA-containing) system. It soon became clear, however, that the CA innervation of the infundibular region is very complex and since it was felt that a detailed neuroanatomical knowledge would be indispensable for correct interpretations of functional and experimental data, a series of studies has been carried out in our laboratory, aiming at a more detailed picture of the topography and organization of the dopamine (DA) and noradrenaline (NA) producing neurons innervating the pituitary-median eminence complex.

Has nerve growth factor a role in the regeneration of central and peripheral catecholamine neurons

Abstract: Publisher Summary This chapter describes the role of nerve growth factor (NGF) in the regeneration of central and peripheral catecholamine neurons. Axonal regeneration can be understood as the attempt of a neuron to re-establish axonal connections severed by a lesion. This process implies a series of complex events involving the reaction of the cell body to the injury, the formation of new axonal sprouts, the outgrowth of the new sprouts, and finally, the establishment of new synaptic connections. The effects of exogenous NGF and of anti-NGF serum were tested on the process of regeneration after axonal degeneration induced by 6-OH-DA. In the adult animal, 6-OH-DA in low to moderate doses is known to induce a selective degeneration of the terminal and paraterminal axon parts of the sympathetic neurons, and therefore this drug offers a very useful tool for reproducible and widespread lesioning of peripheral adrenergic axons. In most of the studied organs, the NGF treatment caused a marked stimulation of the axonal regeneration, as observed at both 9 and 21 days after the 6-OH-DA-induced axonal damage.