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PubMed1980

Ageing of the spinal ganglion neurons in the rat: a radioautographic study following injection of [3H]lysine.

After administration of [3H]lysine to 3- and 24-month-old rats, radioautography demonstrates a significantly less important uptake in the A-type spinal ganglion neurons and in the old animals. This is in agreement with the existence of at least two functional categories of neurons in the spinal ganglion and suggests that protein synthesis is diminished in the old animals. The very fact that incorporation varies between animals of the same age sustains the hypothesis according to which amplitude of ageing is essentially an individual physiological-dependent process.

Aging↗

PubMed1981

Radioautographic study of uptake and storage of indoleamines in the rabbit enterochromaffin cells.

After in vitro intra-arterial injection of tritium-labeled 5-hydroxytryptamine or -hydroxytryptophan ([3H]5-HT or [3H]5-HTP) (5 x 10(-7) M) in the presence of cold noradrenaline (5 x 10(-6) M) into rabbit colon, a clear-cut labeling pattern was observed by radioautography. Labelled cells were observed within the mucosa. The labeling was less important after [3H]5-HTP than after [3H]5-HT injection. Ultrastructural study indicates that labeling is confined to the cytoplasm and coincides with polymorphic secretory granules. Hence these labeled cells display not only APUD cells characteristics but also true neuronal properties.

5-Hydroxytryptophan↗

PubMed1984

Ultrastructural analysis of the noradrenergic innervation of rat supraoptic nucleus.

The noradrenergic innervation of the rat supraoptic nucleus (SON) was examined by high resolution radioautography after animals had been intracerebrally injected with [3H]noradrenaline (NA). In the medial portion of the SON, noradrenergic varicosities were scattered throughout this nucleus, but were preferentially concentrated in its ventral subdivision. 25.5% of these NA varicosities displayed typical synaptic contacts, with either the somatic or proximal dendritic portions of neurosecretory neurons (9.2%) or with small dendritic processes of such neurons (16.3%). The possibility is discussed that at least some of the dendritic NA synapses detected in the ventral subdivision of the SON, which preferentially contains vasopressinergic perikarya, may affect the neurosecretory neurons located in the dorsal part of this nucleus, which preferentially contains oxytocinergic perikarya.

Animals↗

PubMed1984

Radioautographic study of serotoninergic axon terminals in the rat trigeminal motor nucleus.

Serotonin (5-HT) axon terminals were demonstrated in the rat trigeminal motor nucleus (VmN) using radioautography following local injection of tritiated 5-HT. The light microscope radioautographs of the VmN showed silver grain aggregates typical of axonal varicosities having taken up the exogenous 5-HT. In electron microscope radioautographs, labeled 5-HT axon terminals took the form of unmyelinated enlargements, 0.3-2 micron in diameter (average 0.9 micron) containing small clear and large granular vesicles. Out of 182 labeled 5-HT profiles, only 4.9% showed a clear synaptic junction with dendritic branches, indicating the existence of non-synaptic as well as synaptic mechanisms for the 5-HT terminals within the VmN. An estimate of the density of 5-HT varicosities within the VmN was performed on histological radioautographs: the concentration of labeled terminals was evaluated at (1.8 +/- 0.38) X 10(6) per mm3.

Animals↗

PubMed1984

Direct electron microscopic evidence for the coexistence of GABA uptake and endogenous serotonin in the same rat central neurons by coupled radioautographic and immunocytochemical procedures.

In order to detect on the same preparation of rat brain both 5-HT-containing elements and [3H]GABA uptake sites, immunocytochemistry (ICC) and radioautography (RAG) were combined in electron microscopy on sections of dorsal raphe nucleus (DRN) involving supraependymal fibers (SEF). At the ultrastructural level, SEF and DRN dendritic processes could be ICC positive and RAG negative, ICC positive and RAG positive, ICC negative and RAG positive, or negative for both labelings. Because of technical limitations a negative reaction should be interpreted with caution. However, the results constitute another morphological basis for intracellular relationship of endogenous 5-HT and exogenous GABA and provide additional evidence for the possible bipotentiality of some neuronal elements for both transmitters.

Animals↗

PubMed1986

Radioautographic evidence that axons from the area of supraoptic nuclei in the rat project to extrahypothalamic brain regions.

The axonal efferents of neurons of the supraoptic nucleus area were studied by radioautography in the rat after discrete stereotaxic injections of [3H]leucine into this nucleus. Beside a densely labeled pathway running from the nucleus to the posterior pituitary through the internal median eminence, several of the visualized labeled axonal bundles were found to project into various extrahypothalamic regions, including the olfactory bulb, the cortex, the lateral habenula, the subcommissural organ, the amygdala, the mammillary bodies and the locus coeruleus. These results suggest that part of the vasopressin- or oxytocin-containing perikarya located in the supraoptic nucleus constitute the cells of origin of axons which also contain these peptides and which have already been shown to be present in the above extrahypothalamic areas. This also implies that, like the paraventricular nucleus, the supraoptic nucleus is also involved in central extrahypothalamic regulations.

Animals↗

PubMed1986

Major dopamine innervation of the cortical motor areas in the cynomolgus monkey. A radioautographic study with comparative assessment of serotonergic afferents.

Dopamine (DA) and serotonin (5-HT) innervations were revealed by radioautography in primary motor, premotor and supplementary motor (SMA) cortex in Cynomolgus monkeys, using uptake of tritiated amines in vibratome sections under specific conditions that were previously established. DA and 5-HT axons were distributed throughout all cortical layers. A denser DA innervation was found in layers I, III and to a lesser extent layer V with a striking cluster-like arrangement in layer III, particularly in the SMA. 5-HT axons appeared less numerous; their lower density in comparison with DA axons was especially apparent in layer III, particularly in the premotor and motor areas. A DA-5-HT complementarity was thus suggested in this layer. These results suggest that in addition to the motor control exerted through the nigrostriatal pathway, the cortical DA projections could directly modulate the neuronal activity in motor areas. This could be of major importance in the pathophysiology of motor disorders such as Parkinson's disease.

Animals↗

PubMed1988

Mapping of estrogen receptor-producing cells in the rat brain by in situ hybridization.

The localization of cells which produce estrogen receptors in the rat central nervous system was performed using an in situ hybridization technique. For this, we used a synthetic oligonucleotide probe labeled with 35S complementary to the mRNA coding for a fragment (1-24) of estradiol receptor which is not common to the other steroid receptors so far characterized. Radioautography revealed that labeling was present in discrete brain areas. The results obtained with the in situ hybridization agree well with previous results obtained with other techniques. This approach should be very useful to study the effects of different factors on estrogen receptor gene expression in specific brain nuclei and individual neurons.

Animals↗

PubMed1989

Effects of repeated treatment with haloperidol on rat striatal neutral endopeptidase, and on mu- and delta-opioid binding sites: comparison with chronic morphine and chronic kelatorphan.

Neutral endopeptidase (NEP) and mu- and delta-opioid receptor densities were measured in sections of rat striatum by in vitro radioautography with the selective ligands: 3 nM [3H]N-[(2RS)-3-hydroxyaminocarbonyl-2-benzyl-1-oxopropyl]glycine ([ 3H]HACBO-Gly), 3 nM [3H]Tyr-D.Ala-Gly-(NMe)Phe-Gly-ol ([ 3H]DAGO) and 3 nM [3H]Tyr-D-Thr-Gly-Phe-Leu-Thr ([ 3H]DTLET), respectively. Haloperidol treatment (2 mg/kg/day, i.p., 3 weeks), which has been reported to increase enkephalin levels in the striatum, induced a 23% decrease in striatal (posterior level A= +8.4-8.6 mm) NEP labeling (but no change of mu- and delta-sites). In contrast, no change in NEP occurred after chronic morphine (40-160 mg/kg/day, s.c., 4 days) or kelatorphan (10 nmol/h, i.c.v., 7 days), a mixed inhibitor of enkephalin-degrading peptidases.

Animals↗

PubMed1991

Primary dissociated cell culture of embryonic rat metencephalon: presence of GABA in serotonergic neurons.

This study was performed to determine whether neurons, where gamma-aminobutyric acid (GABA) and serotonin (5-HT) coexist, represent neuronal entities which can survive in vitro. In dissociated cultures from 18-day-old embryonic rat metencephalon, it was possible to develop glial and neuronal cells. Among the neurons, some of them, which contain glutamate decarboxylase or are capable of accumulating [3H]GABA are GABAergic; others, containing tryptophan hydroxylase or 5-HT are serotoninergic. By combining radioautography and immunocytochemistry, it was possible to observe neurons where 5-HT and GABA coexist. Cultures might be a suitable model to study the functioning (release or synthesis of both neurotransmitters) of neurons where two classical neurotransmitters coexist.

Animals↗

PubMed1991

Initial process of diffusion of small molecules from blood vessels to the meninges in the young rat.

Pathways taken by peripherally administered small molecules when entering the brain were investigated in 6-day-old rats by radioautography and fluorescence microscopy after intravenous administration and rapid freezing. L-[U-14C]Phenylalanine, [U-14C]sucrose and sodium fluorescein reached the brain within less than 5 seconds. These blood-borne molecules were found in the subarachnoid cisterns and the superficial parenchyma. These results suggest a special permeability of the arachnoid layer and/or the pial vessels. Phenylalanine alone reached the deep parenchyma because of the existence of a specific endothelial carrier.

Animals↗

PubMed1992

Age-related loss of cannabinoid receptor binding sites and mRNA in the rat striatum.

Differences in the distribution of cannabinoid receptor (studied by receptor binding radioautography using the synthetic psychoactive cannabinoid ligand [3H]CP55,940) and its mRNA (studied by in situ hybridization histochemistry using oligonucleotide probes complementary to rat cannabinoid receptor cDNA) have been investigated in the rat striatum during ageing. The striata of old rats (24 months) show a 50% reduction in expression of cannabinoid receptors and mRNA levels when compared with young (3 months) equivalents. Thus, changes in cannabinoid receptor gene expression appear to be partially responsible for age-related loss of these receptors.

Aging↗

PubMed1979

Activation of cyclic AMP-dependent protein kinases in human gut adenocarcinoma (HT 29) cells in culture.

Vasoactive intestinal peptide, secretin, catecholamines and prostaglandin E1 stimulate the accumulation of cyclic AMP in HT 29 cells (see Laburthe, M. et al. (1978) Proc. Natl. Acad. Sci. U.S. 75, 2772-2775). In the present work maximal activation of protein kinases has been obtained at similar or even lower concentrations of the effectors. Maximal stimulation also requires a phosphodiesterase inhibitor. Type I and type II cyclic AMP-dependent protein kinases from basal and stimulated cells have been characterized by DEAE-Sepharose chromatography. Further identidication of the kinase has been carried out by gel electrophoresis and assay of the enzymes in the gel slabs. Comparison of the radioautography patterns of high speed supernatant lysate from basal and stimulated cells shows: First, that one type I and two type II cyclic AMP-dependent protein kinases plus one or two major and two minor cyclic AMP-independent protein kinases are present in HT 29 cells. Second, that all three holoenzymes are fully dissociated upon maximal stimulation, while the activity of the independent kinases appears unchanged.

Adenocarcinoma↗

PubMed1985

Prolactin uptake into liver endocytic components. Reduced sensitivity to chloroquine.

Subfractionation of hepatic Golgi fractions on Percoll gradients revealed two populations of lactogen-receptor enriched components with one pool of rho = 1.040-1.050 and a high-density component of rho = 1.053-1.064. 125I-labelled prolactin uptake into Percoll gradient subfractions demonstrated rapid accumulation into low-density elements and slower accumulation in high-density structures. Electron microscope radioautography demonstrated that silver grains were largely associated with lipoprotein-filled structures. Radiolabel was highly concentrated in these components especially the very pure higher-density component where enrichment over the homogenate was 184-fold at the peak time after injection (10 min). Administered chloroquine accumulated in the higher-density component but not in low-density elements, suggesting that the former are at an acid intraluminal pH. In contrast to the marked effect of chloroquine on insulin uptake into endocytic structures found in Golgi fractions (Posner, B.I., Patel, B.A., Khan, M.N. and Bergeron, J.J.M. (1982) J. Biol. Chem. 257, 5789-5799), little effect of this pH disrupting agent was observed on prolactin uptake. The difference between the effect of chloroquine on 125I-labelled prolactin and 125I-labelled insulin uptake may reflect the greater stability of prolactin-receptor complexes in a low-pH environment.

Animals↗

PubMed1982

Long-term development of mesencephalic dopaminergic neurons of mouse embryos in dissociated primary cultures: morphological and histochemical characteristics.

In 13 and 15 day-old mouse embryos mesencephalic dopaminergic neurons could already be visualized at the level of the mesencephalic flexure by tyrosine hydroxylase immunocytochemistry at day 13. At this time, noradrenergic cells in the locus coeruleus area were not detectable. In most in vitro experiments, dissociated mesencephalic cells of 13 day-old embryos were grown in presence of serum. Four approaches were used to identify the dopaminergic neurons in vitro: fluorescence histochemistry of newly taken up exogenous norepinephrine, radioautography after labelling with (3H) dopamine, tyrosine hydroxylase-like immunoreactivity and fluorescence histochemistry of endogenous stores of catecholamines. Control experiments performed at various times in vitro with selective inhibitors of amine transport into dopaminergic, noradrenergic and serotoninergic neurons indicated that only dopaminergic neurons were detected by these various approaches, noradrenergic neurons being virtually absent from the cultures. The uptake of exogenous norepinephrine was detected already 24 h after plating and preceded the appearance of tyrosine hydroxylase-like immunoreactivity (48 h). The number of neurons revealed by these two techniques increased up to 4 and 10 days, respectively. Endogenous stores of dopamine were only seen after three weeks in vitro by fluorescence histochemistry. At this time, the same number of neurons was revealed whatever the method used. The presence of striatal target cells (co-cultures) affected neither the sequential appearance of the markers nor the number of dopaminergic cells. The two main types of dopaminergic neurons (fusiform and multipolar) described in vivo both in the substantia nigra (A9) and the ventral tegmental area (A10) of adult animals were identified in vitro and their development into well-differentiated neurons can be followed for up to six weeks. This in vitro system seems, therefore, to be particularly suitable for biochemical and electrophysiological studies of these dopaminergic neurons.

Animals↗

PubMed1983

Radioautographic study of the axonal transport of proteins into the sensory nerve endings of avian mechanoreceptors.

The axonal transport of proteins to the nerve endings of Herbst and Grandry sensory receptors has been investigated by electron-microscope radioautography. Soon after the injection of [3H]leucine into the trigeminal ganglia of young ducks, labeled proteins are conveyed along the suborbital sensory nerves to the sensory nerve endings at rates of at least 200-280 mm/day. Most of these rapidly transported proteins accumulate in areas containing vesicles of various kinds and along the axolemmal region. Later, the bulk of labeled proteins migrate along the axons at rates of about 15 mm/day and are distributed mainly to the mitochondria. A small portion of labeled material is transferred to the adjoining modified Schwann and specialized Grandry receptor cells. It is concluded that the transport of proteins from sensory ganglia to sensory nerve endings of mechanoreceptors is conveyed at fast and intermediate rates and is mainly used for the renewal of vesicles, axolemmal constituents and mitochondria.

Animals↗

PubMed1983

Selective retrograde labelling of vestibular efferent neurons with [3H]choline.

Following administration of [3H]choline in the lateral semicircular canal of the cat labyrinth, bidirectional axoplasmic transport [3H]choline and its derivatives was shown by radioautography in the vestibular system. Light-microscopic radioautographs exhibited various patterns of radioautographic labelling. First, a diffuse reaction was observed in vestibular nuclei representing anterograde-labelled, vestibular nerve endings. Second, a heavy labelling limited to perikarya was detected in efferent vestibular neurons and corresponded to retrograde transport. The anterograde migration of [3H]choline is known to be non-selective and is related to synthesis of phospholipids, non-diffusable molecules. In contrast, the retrograde perikaryal labelling seems highly selective and related to the cholinergic specificity of the transmitter. The selectivity of such labelling offers a further possibility of identifying cholinergic neurons and is additional evidence that cholinergic mechanisms are involved in the efferent vestibular control.

Animals↗

PubMed1983

Accumulation of [3H]fucose-labelled glycoproteins in the Golgi apparatus of dorsal root ganglion neurons during inhibition of fast axonal transport caused by exposure of the ganglion to Co2+-containing or Ca2+-free medium.

Previous in vitro studies have established that Co2+-containing or Ca2+-free media interfere with the initiation of the fast axonal transport of proteins. The present study has used light- and electron-microscope radioautography to compare the distribution of [3H]fucose-labelled glycoproteins in neuronal cell bodies of control dorsal root ganglia and ganglia incubated for 16-17 h in Ca2+-free medium or in medium containing 0.18 mM Co2+. The radioautographic reaction in control cell bodies was diffusely scattered throughout the cytoplasm; grain counts revealed that 22% of the reaction was associated with elements of the Golgi apparatus and 78% was over other organelles and the remainder of the cytoplasm. In most experimental cell bodies, 78% of the silver grains were clustered over elements of the Golgi complex whereas other organelles and the remainder of the cytoplasm were comparatively much less labelled; structural alterations of the Golgi apparatus were also produced by the modified media. In parallel studies where the radioactivity in nerve trunks and ganglia was measured by liquid scintillation counting, it was found that the Ca2+-free medium and the Co2+-containing medium both reduced by approximately 80% the quantity of [3H]fucose-labelled glycoproteins which were carried by the fast axonal transport system; they did so without interfering with the incorporation of [3H]fucose into glycoproteins. The results indicate that in the presence of Co2+ or in the absence of Ca2+ the proteins which are destined for fast axonal transport accumulate at the Golgi apparatus of neuronal cell bodies. These results thus suggest that Ca2+ is required for proteins to leave the Golgi region in transit to the fast axonal transport system.

Animals↗