Catecholamine Fibers Research Articles

Association of sympathetic axons in denervated hippocampus to intracerebral vasculature. I. Fluorescence histochemistry combining glyoxylic acid and pontamine sky blue.

Combining glyoxylic acid and pontamine sky blue fluorescence methods allows simultaneous visualization of catecholamine fibers and the intra-hippocampal vascular bed. The normal noradrenergic innervation of the hippocampal formation is not closely associated with the vasculature in any region. However, following lesions of the septo-hippocampal fibers, norepinephrine-containing sympathetic fibers course along the penetrating arterioles into the parenchyma of regio inferior and the area dentata. Within the respective cell layers, the anomalous sympathetic axons collateralize freely, thus suggesting a dual relationship with the vasculature and with the neuropil of selective hippocampal zones.

Comparative anatomy of brain monoaminergic neurons in New World and Old World monkeys.

A comparison of the distribution of brain monoamine neurons in several New World and Old World monkeys was undertaken using the Falck-Hillarp formaldehyde histofluorescence technique. The overall organization of the monoamine neurons was very similar in all species, although subtle variations were found. Catecholamine (noradrenaline and dopamine) and indoleamine (serotonin) cell bodies corresponding to groups A1-A7, A8-A10, and B1-B9, respectively were found throughout the brainstem. A few catecholamine (dopamine) cells equivalent to groups All and A12 in the diencephalon were also observed. Noradrenaline neurons, rather than those of the dopamine and serotonin systems, tended to be less numerous in the New World monkeys. Ascending catecholamine and indoleamine fiber bundles were observed in most monkeys. It is interesting that fibers corresponding to the "ventral noradrenaline bundle" appeared to be much finer in the common marmoset and tamarin than in other species. In addition, a substantial catecholamine (noradrenaline) innervation of the diencephalon was noted in all the Old World monkeys, while a much lower overall terminal density was apparent in the New World forms.

The catecholaminergic nerve supply to small intracerebral vessels following a cold injury to the mouse cortex.

A cold lesion was produced in the mouse parietal cortex. The damaged area was examined for alterations in the catecholamine fibres either by fluorescence microscopy or by electron microscopy. Within 24 h of injury many damaged catecholaminergic nerves were observed in close association with small intracerebral blood vessels. This relationship between nerves and blood vessels was not apparent in the control cortex. In the electron microscope, swollen non-myelinated axons containing an accumulation of dense-cored vesicles were observed close to the vessel wall but separated from it by astrocytic process. Six days after injury regenerating catecholaminergic nerve fibres were found close to immature capillaries. Axonal-like profiles containing dense-cored vesicles were observed adjacent to the endothelial call basement membrane. The number of regenerating nerves declined with time and the only fluorescent catecholaminergic nerves that remained 12 weeks after injury were in an area known to be rich in capillaries.

Mutant mouse tottering: selective increase of locus ceruleus axons in a defined single-locus mutation.

The central catecholamine neuron system in the mutant mouse tottering was examined by fluorescence histochemistry and biochemical analysis of catecholamine content. This single-locus neurological mutation expresses a reproducible alteration in central nervous system physiology characterized by spontaneous spike-wave and focal motor seizures in the absence of any previously recognized disturbance of cellular organization or brain size. Histochemical analysis showed a significant increase in the number of noradrenergic axons in terminal fields innervated by the nucleus locus ceruleus when compared with the wild type. A concomitant 100-200% rise in norepinephrine levels is found in the same areas, including hippocampus, cerebellum, and dorsal lateral geniculate. Catecholamine fibers and transmitter content in areas innervated by a second major noradrenergic system arising from the brainstem lateral tegmental neurons are unaltered. The terminal axons and transmitter content were both unchanged in nuclei receiving a dense dopaminergic innervation. Despite the hypertrophy of the locus ceruleus axonal plexus, the number and size of locus ceruleus cell somata were identical in both wild-type and tottering mice. These findings are consistent with a specific gene-linked alteration of developmental events controlling the number of axons produced by a single neuronal population in the mammalian brain.

Norepinephrine-containing terminals in kitten visual cortex: Laminar distribution and ultrastructure

The laminar distribution of monoamine-containing terminals in the visual cortex (areas 17 and 18) of 6- to 8-week-old kittens was studied with a modified glyoxylic acid histofluorescence method. The ultrastructure of monoamine-containing terminal boutons in cortical tissues fixed with glyoxylic acid perfusion followed by immersion in potassium permanganate was also studied in serial sections. In both coronal and sagittal planes, rich innervation of catecholamine-containing fibers and terminals was found throughout all 6 cortical layers. Intensely fluorescent stem fibers, which are preterminal fibers in the white matter, entered layer VI from the white matter after veering abruptly towards the cortical surface. While the stem fibers ran towards the surface, many collateral terminal fibers branched out in all directions in the middle layers; a dense plexus of catecholamine fibers and terminals was found mostly in layers II and III. Reaching the superficial layer, the stem fibers gave off terminal fibers which ran parallel to the surface. Monoamine-containing terminal boutons were identified by electron microscopy as small bulges which contained dense-cored vesicles. About 10% of the monoamine-containing boutons showed the usual synaptic membrane specialization suggesting synapse formation. Another 10% of the monoamine boutons showed only some characteristic features such as widening of the associated intermembrane space, and aggregation and contact of cored vesicles with the presynaptic membrane. The remaining 80% of the monoamine boutons failed to show any of the above described properties. The 2 types of monoamine boutons with classical synaptic features were seen in all layers, particularly II and III, but not in layer VI. The most frequent target of monoamine boutons in all 6 layers seemed to be dendritic shafts. The few axo-spiny and axo-somatic contacts observed occurred in the superficial and deep layers, respectively. The circumstantial evidence suggested that the monoamine visualized in the current study of either histofluorescence or electron microscopy was in fact norepinephrine rather than dopamine and serotonin. The rich innervation of all cortical layers with catecholamine-containing boutons is consistent with noradrenaline being a factor in modifying the plasticity of neurons in the visual cortex.

Innervation of embryonic rat cerebral cortex by catecholamine-containing fibers.

Catecholamine-containing neuronal processes penetrate to the outer superficial layers of the developing neocortex via the lateral neocortex anlage by embryonic day (ED) 16, only 48 hours after the final cell division of the catecholamine neurons in the mesencephalon and pons-medulla. Sagittal sections were taken from a series of perfused embryos at precise time-intervals after insemination. The corpus striatum receives a large catecholamine input and serves as a reference for tracing the very fine varicose processes that course through the caudate nucleus to innervate the more rostral structures of the developing neocortex cerebri. The input fibers to the neocortex arrive via three to four small fiber bundles, entering chiefly at the ventro-rostral aspect. The bundles than bifurcate into the deep and superficial layers of the cortex. Between ED16 to ED21 the innervation progresses in ventral to dorsal and rostral to caudal directions. Embryonically, fluorescent fibers are observed in the outermost superficial layer and in the intermediate zone, below the cortical plate; only rarely are they seen crossing the cortical plate. The demonstration of monoaminergic neuronal fibers reaching neocortical structures by ED16 adds further weight to the speculation that they may play a role in induction and differentiation, and suggests that post-natal experimental manipulations using ascending-bundle lesions will have been performed at least five days after the arrival of catecholamine fibers at their cortical destinations.

Indoleamines in the pineal complex of Lampetra planeri (Petromyzontidae). A fluorescence microscopic and microspectrofluorimetric study.

Using the technique of Falck and Hillarp, the pineal and parapineal organs of Lampetra planeri were found to exhibit a labile yellow fluorescence characteristic of indoleamines. Microspectrofluorimetric analysis of the yellow fluorophores yielded emission and excitation spectra very similar to those of the melatonin precursors serotonin (5-HT) or 5-hydroxytryptophan (5-HTP). 5-HT/5-HTP fluorophores are concentrated essentially in the region of the atrium, along the pineal tract and in the rostral part of the parapineal organ. The fluorescence is strong in early autumn, decreases in winter and is weak or absent in spring, implying a seasonal variation in indoleamine metabolism. Fluorescence intensity increases after injections of nialamide or nialamide and 5-HTP and is lowered by injection of reserpine. Indoleamine fluorescence is localized in the recently identified sensory-type cells: the photoneuroendocrine cells (Meiniel, 1980). The ependymal-like cells, the sensory neurons and the classical photoreceptor cells (Collin, 1969 a) do not appear to be involved in indole metabolism. The absence of catecholamine fibres in the perivascular spaces suggests that indole biosynthesis is regulated via the direct photosensitivity of the pineal complex.

Aging of central endocrine neurons and their aminergic afferents

Characteristics of central endocrine neurons and their catecholaminergic afferent innervation patterns during the aging process were examined in the Fischer 344 rat using a combined histofluorescence-immunocytochemical approach. Staining of peptidergic target neurons remained strong and largely unchanged with age for neurophysin, LHRH and somatostatin-containing perikarya. A sharp decline was seen in the noradrenergic innervation patterns of the supraoptic nucleus; as much as a 50% drop in varicosity-perikaryal juxtapositions occured with age. This terminal field decline was paralleled by similar changes in LHRH and somatostatin staining of fibers in the median eminence. An hypothesis that target neuron peptide may be essential for the maintenance of catecholaminergic afferent fibers was tested in the vasopressin-deficient Brattleboro rat wherein catecholamine fiber density appeared reduced in the vasopressin deficient portions of the supraoptic nucleus.

Quantitative radioautographic light and electron microscopic analysis of the localization of monoamines in the median eminence of the rat. I. Catecholamines.

By means of light and electron microscopic radioautography a quantitative study of the regional distribution of catecholamines in the median eminence of the rat was carried out. One hour after intraventricular injection of 3H-dopamine the highest radioautographic reaction was recorded in the external zone, especially in the lateral palisade zone where many neurosecretory terminals are separated from the basal lamina of the portal pericapillary space by a glial "cuff". This area showed the highest percentage (52%) of labelled catecholamine containing neurosecretory terminals as well as the maximal silver grain density per one terminal. In the medial palisade zone where direct neurovascular contacts with the capillary loops prevail, only 27 per cent of neurosecretory terminals were found to harbour tritiated dopamine. On the average 35 per cent of neurosecretory terminals in the median eminence of the rat contain catecholamines (both dopamine and noradrenaline). Pretreatment of animals with recretory terminals as well as grain density over terminals were decreased in both the medial and lateral palisade zones, although to a lesser degree in the latter. The site of origin of catecholamine fibers as well as the mode of catecholamine action at the level of the median eminence are discussed.

Decreased locomotor and investigatory exploration after denervation of catecholamine terminal fields in the forebrain of rats.

Exploratory behaviors were examined after bilateral microinjections of 6-hydroxydopamine into two hypothalamic sites that produced different patterns of denervation of forebrain catecholamine terminal fields. After anterolateral injections rats locomoted and reared less in a novel open field, responded abnormally to changes in the degree of novelty of the open field, and investigated a novel object less. These are deficits in exploratory behavior because they were not secondary to the inhibition of open-field behavior by hyperemotionality, by general motor disability, or by the failure to detect novel spaces or objects. Such anterolateral injections produced loss of catecholamine fibers, determined histochemically, in neocortical, hippocampal, anterolateral hypothalamic, mesolimbic, mesocortical, and anteromedioventral striatal terminal fields and loss of dopaminergic perikarya in the A10 and anteromedial A9 cell groups. No deficits in exploratory behaviors occurred, however, after bilateral anteromedial 6-hydroxydopamine injections that denervated neocortical, hippocampal, and anteromedial hypothalamic catecholamine terminal fields. A critical forebrain catecholaminergic innervation for exploratory responses to novel stimuli may be within areas that were denervated by anterolateral but not by anteromedial hypothalamic 6-nydroxydopamine injections. These areas are mesolimbic, mesocortical, anteromedioventral, and anterolateral hypothalamic terminal fields.

Regeneration of monoaminergic and cholinergic neurons in the mammalian central nervous system

Regeneration of monoaminergic and cholinergic neurons in the mammalian central nervous system

Descending monoaminergic pathways in the primate spinal cord.

The distribution of monoamine axons and terminals within the spinal cord of a primate (Macaca mulatta) was studied with the Falck-Hillarp histofluorescence technique for the demonstration of biogenic amines. Catecholamine and indoleamine varicosities appeared qualitatively similar to those previously reported for the rat although the indoleamine terminals were difficult to visualize and were not studied in great detail. Catecholamine fibers innervate the substantia gelatinosa, marginal layer, intermediolateral cell column, ventral horn and the region surrounding the central canal. The location of monoamine axons, as revealed by spinal cord ligation, corresponds to that in the rat and cat with the exception of the dorsolateral region of white matter where fluorescent axons are not visible in the primate.

Catecholamine innervation of the basal forebrain III. Olfactory bulb, anterior olfactory nuclei, olfactory tubercle and piriform cortex

The catecholamine innervation of the olfactory bulb, anterior olfactory nuclei, olfactory tubercle and piriform cortex was studied in the rat using biochemical analysis and fluorescence histochemistry. Biochemical studies demonstrate a moderate norepinephrine (NE) content in all olfactory structures, a high dopamine (DA) content in the olfactory tubercle and a low DA content in the olfactory bulb, anterior olfactory nucleus and piriform cortex. Following locus coeruleus lesions NE content decreases 71% in the olfactory bulb, 82% in the anterior olfactory nucleus, 62% in olfactory tubercle and 77% in piriform cortex...

カテコールアミン蛍光組織化法学研究

The distribution of catecholamine containing neurons and fibers was studied in the rabbit medulla-pontine-tegmentum by the chloralhydrate-glyoxylic acid-formaldehyde method.There are fundamental similarities between the rabbit and the other mammals on the catecholamine distribution. Most of the catecholamine fluorescent cell bodies in the rabbit are located within the nucleus locus coeruleus, subcoeruleus and substantia nigra in the pontine tegmentum.They are more extensive than those of the rat, monkey and more connective than those of the dog and cat.There are two main catecholamine fiber systems at the medulla level. One is ventrolateral catecholamine pathway originating from the area corresponding to A1 in the rat and the other is the dorsomedial catecholamine pathway originating from the area corresponding to A2 in the rat.These two pathways associate with the upper medulla oblongatae level.One catecholamine containing cell group extends toward dorsolateral in the nucleus reticularis lateralis of the rabbit, but it has not been found in the rat.

De- and regeneration of brain serotonin neurons following 5,7-dihydroxytryptamine treatment: Effects on serum LH, FSH and prolactin levels in male rats

5,7-Dihydroxytryptamine (5,7-DHT), injected intraventricularly at a dose of 100 μg into adult male rats pretreated with desipramine (DMI), caused a substantial injury to the central serotonin system without any significant damage to the central catecholamine fiber systems. This treatment produced a 60–75% drop in forebrain 5-HT, a 65–80% reduction in hypothalamic [3H]5-HT uptake, and a 65–75% reduction in the hypothalamic synthesis of [3H]5-HT from [3H]tryptophan in vitro, at 4–12 days after injection. Forebrain 5-HT levels remained low up to 55 days (the latest time point studied) whereas the [3H]5-HT uptake and the serotonin forming capacity in the hypothalamus showed a gradual recovery within two months after injection. In the DMI-5,7-DHT treated rats, there was a significant reduction in serum LH, but not FSH, lasting for 26 days after low dose (100 μg) and for 69 days after a higher one (150 μg). The time course of recovery of serum LH levels seemed to correlate well with the regrowth of sprouting serotonin fibers in the hypothalamus (as indicated by the recovery of [3H]5-HT uptake and [3H]5-HT synthesis). Stress-induced prolactin release (exposure to ether vapour) was not affected by the DMI-5,7-DHT treatment. The results indicate that the serotoninergic neuron system has a facilitatory role in the regulation of pituitary LH secretion in the male rat. They further indicate that stress-induced prolactin release is unimpaired in animals with a damaged serotoninergic system. Moreover, our data lend support to the idea that the recovery of the neuroendocrine regulatory mechanisms is caused by an actual regeneration of the drug-lesioned serotonin axons.

Cerebellar contributions to the papez circuit

Cerebellar influences on the various substructures in the Papez Circuit are indicated by the following. 1. Anatomical studies indicate that the major midbrain areas to which this circuit projects are : 1) ventral tegmental area; 2) interpeduncular area; and 3) periaqueductal gray areas; and these same areas project back to the limbic system. There are projections to these regions from the cerebellar nuclei, as indicated by terminal degeneration studies which show that cerebellar nuclei connect, mostly by fine fibers, with a continuum of cells located on either side of the midline in the ventral tegmentum of the midbrain. Observations that the cerebellum also projects to the locus ceruleus (NA system) and VTA (DA system) indicate that cerebellar influences can also reach the limbic areas via the catecholamine fiber bundles. 2. Electrophysiological studies indicate that vermiam and fastigial stimulation induce evoked responses in the basolateral amygdala, the hippocampus, and the septum, with latencies to the peak of first wave ranging from 4 to 8 msec and to the second wave of 16-29 msec. Citations from the physiological literature indicate that electrical stimulation of the cerebellum, especially the vermis, can modify a wide range of responses which involve functional activities of either the sympathetic or parasympathetic nervous systems. 3. Studies on electrically induced afterdischarges in the septum, hippocampus, and amygdala indicate that cerebellar stimulation can shorten the duration of or terminate the afterdischarges, and the site of lowest threshold is the midline cortex. Focal cooling of the vermis promotes prolongation of the afterdischarges as does pretreatment of animals with 6-OH dopamine. Chemical lesions in the catecholamine system induced by 6-OH dopamine reduce the effectiveness of the cerebellar stimulation, as do lesions of nucleus fastigii. These data are interpreted to indicate that the cerebellum can exert a tonic suppressor (inhibitory?) influence on substructures within the Papez Circuit. 4. Citations from animal behavioral studies indicate that electrical stimulation of the anterior cerebellum can induce responses such as arousal, predatory attack, and feeding which mimic those obtained by amygdaloid stimulation. Fastigial stimulation can produce drowsiness and EEG changes which resemble the sleep patterns resulting from stimulation of the ventral amygdala.

Histochemical mapping of catecholamine neurons and fiber pathways in the pontine tegmentum of the dog

The distribution of catecholamine-containing neurons and fiber pathways were studied in the dog's pontine tegmentum by the Falck-Hillarp method. There are fundamental similarities between the dog and other mammals. Most catecholamine fluorescent cell bodies in the dog are located within the nucleus locus coeruleus and subcoeruleus in the pontine tegmentum. They are more diffuse and extensive than in the rat, monkey and human, and rather similar to those of the cat. In this study, catecholamine fiber pathways were clearly traced without using the lesion-degeneration technique. The dorsal pathway from the locus coeruleus consists of more compact bundles of non-varicose fibers than the rat, cat and monkey. It runs parallel to the mesencephalic tract of the trigeminal nerve in pons and midbrain. The ventral pathway courses as loosely arranged varicose fibers in the midreticular formation of the pons and sends axon collaterals to the caudal midbrain to form a dense network of varicose fibers. There are fluorescent plexi of fine varicose fibers at the ventromedial and dorsolateral aspect of the superior cerebellar peduncle. Cells of the medial and lateral parabrachial nucleus, in addition to those of locus coeruleus, send fluorescent fibers to this peduncle. No fluorescent fibers are found in other peduncles.

Cardiovascular changes following DOCA/NaCl or conditioning in 6-hydroxydopamine-treated rats

Two intracisternal injections of 200 μg 6-hydroxydopamine reduced brain catecholamine levels 90% and significantly lowered resting heart rate and blood pressure. In a classical aversive conditioning paradigm, 6-hydroxydopamine-treated rats displayed little or no conditioned heart rate response in anticipation of shock, but a potentiated unconditioned response to shock itself. The alteration in heart rate responses may have been due in part to alterations in general activity. Although 6-hydroxydopamine treatment did not abolish the hypertension caused by DOCA/NaCl treatment following uninephrectomy, the increase in blood pressure was significantly less than the blood pressure increase in control rats receiving this treatment. The 6-hydroxydopamine treatment, however, concomitantly reduced the amount of NaCl consumed after DOCA. Since peripheral tyrosine hydroxylase activity and amine levels were not significantly altered by 6-hydroxydopamine treatment, the alterations in cardiovascular responses following 6-hydroxydopamine must result from its central actions. Although 6-hydroxydopamine administration markedly altered the cardiovascular responses to conditioned stimuli, shock, and DOCA/NaCl treatment, it is difficult to ascribe these alterations to ablation of central catecholamine fibers participating directly in cardiovascular control. The link between destruction of catecholamine fibers and changes in cardiovascular responses may be secondary to changes in activity or ingestive behavior.

Ascending monoamine-containing fiber pathways related to intracranial self-stimulation: Histochemical fluorescence study

Lesions made via self-stimulation electrodes in the medial forebrain bundle (MFB) of rats always resulted in monoamine accumulation, as studied with the histochemical fluorescence method. Build-up was often in the monoamine systems of the MFB itself, those systems being the ventral norepinephrine bundle, the nigro-neostriate bundle, and the mesolimbic fibers. In other cases, build-up was restricted to a bundle of fibers dorsomedial to the MFB, probably originating in the locus coeruleus or the subcoeruleus area. In still other instances, build-up was seen in both this dorsal bundle of fibers and the catecholamine systems of the MFB. Electrodes in rats with sites of implantation in the region of the A1, A2 and A5 cell groups of origin of the ventral norepinephrine system, as identified with combined Nissl and histochemical examination, were never positive with respect to self-stimulation; nor were placements in this ventral system caudal to the origin of the dorsal bundle positive with respect to that behavior. These results argued against the association of the ventral system with self-stimulation. By implication, the catecholamine fibers of the MFB which are capable of supporting self-stimulation might be the two ascending dopamine systems of the ventral mesencephalic tegmentum. Lesions made via positive electrodes in the vicinity of the brachium conjuctivum always resulted in monoamine build-up in the dorsal norepinephrine fiber system. In sum, our results implicate the A9 and A10 dopamine ventral midbrain systems and the A6 norepinephrine dorsal bundle in intracranial self-stimulation.

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

AbstractThe 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: 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. 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. 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. 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.