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Journal ArticleDOI

Differential projections of the nucleus raphe dorsalis and nucleus raphe centralis as revealed by autoradiography.

28 Feb 1975-Brain Research (Elsevier)-Vol. 85, Iss: 2, pp 205-210
About: This article is published in Brain Research.The article was published on 1975-02-28. It has received 266 citations till now. The article focuses on the topics: Dorsal raphe nucleus & Serotonergic cell groups.
Citations
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Journal ArticleDOI
TL;DR: The differential projections from the dorsal raphe and median raphe nuclei of the midbrain were autoradiographically traced in the rat brain after 3H‐proline micro‐injections to identify six ascending fiber tracts.
Abstract: The differential projections from the dorsal raphe and median raphe nuclei of the midbrain were autoradiographically traced in the rat brain after 3H-proline micro-injections. Six ascending fiber tracts were identified, the dorsal raphe nucleus being the sole source of four tracts and sharing one with the median raphe nucleus. The tracts can be classified as those lying within the medial forebrain bundle (dorsal raphe forebrain tract and the median raphe forebrain tract) and those lying entirely outside (dorsal raphe arcuate tract, dorsal raphe periventricular tract, dorsal raphe cortical tract, and raphe medial tract). The dorsal raphe forebrain tract lies in the ventrolateral aspect of the medial forebrain bundle (MFB) and projects mainly to lateral forebrain areas (e.g., basal ganglion, amygdala, and the pyriform cortex). The median raphe forebrain tract lies in the ventromedial aspect of the MFB and projects to medial forebrain areas (e.g., cingulate cortex, medial septum, and hippocampus). The dorsal raphe cortical tract lies ventrolaterally to the medial longitudinal fasciculus and projects to the caudate-putamen and the parieto-temporal cortex. The dorsal raphe periventricular tract lies immediately below the midbrain aqueduct and projects rostrally to the periventricular region of the thalamus and hypothalamus. The dorsal raphe arcuate tract curves laterally from the dorsal raphe nucleus to reach the ventrolateral edge of the midbrain and projects to ventrolateral geniculate body nuclei and the hypothalamic suprachiasmatic nuclei. Finally, the raphe medial tract receives fibers from both the median and dorsal raphe nuclei and runs ventrally between the fasciculus retroflexus and projects to the interpeduncular nucleus and the midline mammillary body. Further studies were done to test whether the fiber tracts travelling in the MFB contained 5-HT. Unilateral (left) injections of 5,7-dihydroxytryptamine (5 μgm/400 nl) 18 days before midbrain raphe microinjections of 3H-proline produced a reduction in the grain concentrations in all the ascending fibers within the MFB. Furthermore, pharmacological and behavioural evidence was obtained to show that the 5-HT system had been unilaterally damaged; these animals displayed preferential ipsilateral turning in a rotameter which was strongly reversed to contralateral turning after 5-hydroxytryptophan administration. The results show that DR and MR nuclei have numerous ascending projections whose axons contain the transmitter 5-HT. The results agree with the neuroanatomical distribution of the 5-HT system previously determined biochemically, histochemically, and neurophysiologically. The midbrain serotonin system seems to be organized by a series of fiber pathways. The fast transport rate in these fibers was found to be about 108 mm/day.

1,895 citations

Journal ArticleDOI
TL;DR: The VTA contains the A10 group of DA containing neurons, which have been grouped into nuclei to be found on the floor of the midbrain tegmentum--Npn, Nif, Npbp and Nln rostralis and caudalis and the role of the VTA as a mediator of dialogue with the frontostriatal and limbic/extrapyramidal system is discussed.

906 citations

Journal ArticleDOI
TL;DR: The ascending projections of serotonin neurons of the midbrain raphe were analyzed in the rat using the autoradiographic tracing method and a number of fibers leave the major group to ascend along the fasciculus retroflexus.
Abstract: The ascending projections of serotonin neurons of the midbrain raphe were analyzed in the rat using the autoradiographic tracing method. Axons of raphe serotonin neurons ascend in the ventral tegmental area and enter the medial forebrain bundle. A number of fibers leave the major group to ascend along the fasciculus retroflexus. Some fibers enter the habenula but the majority turn rostrally in the internal medullary lamina of the thalamus to innervate dorsal thalamus. Two additional large projections leave the medial forebrain bundle in the hypothalamus; the ansa peduncularis-ventral amygdaloid bundle system turns laterally through the internal capsule into the striatal complex, amygdala and the external capsule to reach lateral and posterior cortex, and another system of fibers turns medially to innervate medial hypothalamus and median eminence and form a contrelateral projection via the supraoptic commissures. Rostrally the major group in the medial forebrain bundle divides into several components: fibers entering the stria medullaris to terminate in thalamus; fibers entering the stria terminalis to terminate in the amygdala; fibers traversing the fornix to the hippocampus; fibers running through septum to enter the cingulum and terminate in dorsal and medial cortex and in hippocampus; fibers entering the external capsule to innervate rostral and lateral cortex; and fibers continuing forward in the medial olfactory stria to terminate in the anterior olfactory nucleus and olfactory bulb.

793 citations

Journal ArticleDOI
TL;DR: Ascending projections from the dorsal raphe nucleus were examined in the rat by using the anterograde anatomical tracer, Phaseolus vulgaris leucoagglutinin (PHA‐L).
Abstract: Ascending projections from the dorsal raphe nucleus (DR) were examined in the rat by using the anterograde anatomical tracer, Phaseolus vulgaris leucoagglutinin (PHA-L). The majority of labeled fibers from the DR ascended through the forebrain within the medial forebrain bundle. DR fibers were found to terminate heavily in several subcortical as well as cortical sites. The following subcortical nuclei receive dense projections from the DR: ventral regions of the midbrain central gray including the 'supraoculomotor central gray' region, the ventral tegmental area, the substantia nigra-pars compacta, midline and intralaminar nuclei of the thalamus including the posterior paraventricular, the parafascicular, reuniens, rhomboid, intermediodorsal/mediodorsal, and central medial thalamic nuclei, the central, lateral and basolateral nuclei of the amygdala, posteromedial regions of the striatum, the bed nucleus of the stria terminalis, the lateral septal nucleus, the lateral preoptic area, the substantia innominata, the magnocellular preoptic nucleus, the endopiriform nucleus, and the ventral pallidum. The following subcortical nuclei receive moderately dense projections from the DR: the median raphe nucleus, the midbrain reticular formation, the cuneiform/pedunculopontine tegmental area, the retrorubral nucleus, the supramammillary nucleus, the lateral hypothalamus, the paracentral and central lateral intralaminar nuclei of the thalamus, the globus pallidus, the medial preoptic area, the vertical and horizontal limbs of the diagonal band nuclei, the claustrum, the nucleus accumbens, and the olfactory tubercle. The piriform, insular and frontal cortices receive dense projections from the DR; the occipital, entorhinal, perirhinal, frontal orbital, anterior cingulate, and infralimbic cortices, as well as the hippocampal formation, receive moderately dense projections from the DR. Some notable differences were observed in projections from the caudal DR and the rostral DR. For example, the hippocampal formation receives moderately dense projections from the caudal DR and essentially none from the rostral DR. On the other hand, virtually all neocortical regions receive significantly denser projections from the rostral than from the caudal DR. The present results demonstrate that dorsal raphe fibers project significantly throughout widespread regions of the midbrain and forebrain.

789 citations

References
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Journal ArticleDOI
TL;DR: There are several reasons for thinking that this method may offer a number of advantages over other currently available techniques, and it should be possible to do this by locally injecting radioactively labeled precursors of proteins or other macromolecules into the brain or spinal cord.

1,523 citations

Journal ArticleDOI
01 Sep 1958-Brain
TL;DR: Recent studies in the rat have confirmed much earlier descriptions of widespread distributions of the fornix system to the diencephalon and the rostral mid-brain regions.
Abstract: Recent studies in the rat (Guillery, 1956; Nauta, 1956) have confirmed much earlier descriptions of widespread distributions of the fornix system to the diencephalon and the rostral mid-brain regions. Besides the well-known massive hippocampal projections to the septal region (Ganser, 1882) and the mammillary body (Gudden, 1881), fornix components have been traced from the hippocampus to the preoptic region and the hypothalamus (Cajal, 1911), to the anterior nuclear complex and rostral intralaminar nuclei of the thalamus (Gudden, 1881; Vogt, 1898; Cajal, 1911), and to the rostral part of the central grey mid-brain substance (Edinger and Wallenberg, 1902).

941 citations

Journal Article
TL;DR: The aim of this investigation was to study how penicillin is distributed from the blood to different body tissues and how it is bound, inactivated and excreted and to provide possibilities of studying the dif­ ferent ways of excretion as well as the problem of accumulation in the organs.
Abstract: The aim of this investigation was to study some of the pharmacologie properties of penicillin; how it is distributed from the blood to different body tissues and how it is bound, inactivated and excreted. In order that penicillin shall exert its antibacterial activity in the body it must come into contact with the pathogenic microbes and its concentration in the immediate vicinity of these must be sufficiently high. A careful study of the distribution pattern in both normal and pathologically changed tissues is therefore of therapeutic interest. Biosynthetically prepared penicillin containing the radioisotope S has been pre­ pared and its distribution studied with autoradiographic technique. The culture and extraction methods employed in the preparation of S-labelled benzylpenicillin are described and general problems connected with the biosynthesis of radiopenicillin discussed. The autoradiographic technique was adapted to the requirements imposed by the water solubility of penicillin and also to the desire to obtain survey pictures e. g. of whole mice. Experiences of freeze-drying technique compared to freeze-room sectioning are also discussed. The varying density of large histologie survey sections of whole mice was investigated with quantitative betaradiography. This investigation formed the basis for calculation of self-absorption of the radiation from a section. Survey autoradiographs illustrating the distribution of penicillin in adult mice at different times after intravenous injection are given. Large survey autoradiographs of pregnant animals permitted studies of tracer distribution in the foetus and foetal fluids in the same picture as the mother. Detail autoradiographs are shown illustrating the distribution of penicillin in regions of special clinical interest such as the brain, eye, sinuses of the skull, nasal conchae, teeth and paradental tissues, synovial cavities, skin, bone-marrow, mammary glands, and postparturiant uterus. The autoradiographic investigation also provided possibilities of studying the dif­ ferent ways of excretion as well as the problem of accumulation in the organs. Some autoradiographic observations were also made on the penetration of penicillin into abscesses and dry necroses. (In the cases investigated penicillin passed the abscess membrane but the further diffusion towards the centre of the abscess was very unsatis­ factory in the chronic cases. The penicillin penetrated very poorly into dry necrotic areas.) Geiger-Müller counter measurements were used to study the penetration of penicillin into blood and carcinoma cells, its binding to plasma proteins, and its volume of distri­ bution in the body. A paper electrophoretic investigation of urine from animals treated with radioactive penicillin showed the presence of two radioactive components. The major component had the same mobility as penicillin and was biologically active. The smaller component with a higher mobility was biologically inactive. I ts rate of migration corresponded with that of S-penicilloic acid prepared in vitro by the inactivation of S-penicillin. The distribution of penicilloic acid in the body showed no obvious variations from the distribution of penicillin according to survey autoradiographs. Autoreview.

622 citations

Journal ArticleDOI
TL;DR: The evidence presented suggests first, that the degree of localization at the injection site is compatible with approaching some problems in neuroanatomy; second, that anterograde transport of the marker protein does not appear to confound the interpretation of retrogradely labeled cell bodies; third, that many, though not all, afferent cell populations can be identified.

521 citations