Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DIENCEPHALON”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources
PubMed1994

The distribution of GABA-immunoreactive neurons in the brain of the silver eel (Anguilla anguilla L.).

The distribution of GABA-immunoreactivity was studied in the brain of the silver eel (Anguilla anguilla) by means of antibodies directed against GABA. Immunoreactive neuronal somata were distributed throughout the brain. Positive perikarya were detected in the internal cellular layer of the olfactory bulb, and in all divisions of the telencephalon, the highest density being observed along the midline. Numerous GABA-reactive cell bodies were found in the diencephalon, particularly in the preoptic and tuberal regions of the hypothalamus, and the dorsolateral, dorsomedial and ventromedial thalamic nuclei. In the optic tectum, the majority of GABA-positive cell bodies were located in the periventricular layer. A number of immunolabeled cell bodies were observed in different tegmental structures, notably the torus semicircularis. In the cerebellum, the Purkinje cells were either very intensely or very weakly immunoreactive. In the rhombencephalon, reactive cell bodies were observed in the eminentia granularis, the valvula cerebellaris, the octavolateral nucleus, the lobus vagus and in the vagal and glossopharyngeal motor nuclei. Intensely immunoreactive axons and terminals were observed in the external granular layer and internal cellular layer of the olfactory bulb. In the telencephalon, the highest density of reactive fibres and boutons was found in the fields of the medial wall. Many immunolabeled fibres were seen in the medial and lateral forebrain bundles. In the diencephalon, intense labelling of fibres and terminals were observed in the nuclei situated close to the midline. In the optic tectum the highest density of reactive fibres was seen in the sfgs, the layer to which the retina projects massively. Finally, in the rhombencephalon the strongest labelling of neurites was observed in the nuclei of the raphé, the nucleus octavocellularis magnocellularis and the nuclei of the IXth and Xth cranial nerves. The GABAergic system of the eel, which is well developed, appears to be generally comparable to that described in tetrapod vertebrates.

Anguilla↗
PubMed1991

Regional central serotonin receptor binding in rats treated chronically with high-dose 5-hydroxy-L-tryptophan.

The serotonin (5-HT) precursor 5-hydroxy-L-tryptophan (L-5-HTP) exerted differential regional effects on central 5-HT receptors in rats treated chronically by intraperitoneal injections of large incremental doses (50-200 mg/kg). There were significant reductions in Bmax of agonist-labelled (-35%) and antagonist-labelled (-20%) 5-HT2 sites in cortex but no changes in brainstem. KD and nH were unaffected by L-5-HTP. Bmax of 5-HT1 sites (unsubtyped) was reduced 16% in cortex and 18% in spinal cord, but the changes were not significant. Brainstem 5-HT1 sites were unaffected. Studies at a single isotope concentration in other regions revealed significant reductions of antagonist-labelled 5-HT2 specific binding in diencephalon (-26%) but not septum, and of 5-HT1 binding in diencephalon (-25%) and cerebellum (-30%) but not in hippocampus or striatum. Absence of L-5-HTP-evoked changes in 5-HT receptors in brainstem may have implications for L-5-HTP-responsive and brainstem-mediated human myoclonic disorders.

5-Hydroxytryptophan↗
PubMed1980

The distribution of aminergic neurones and their projections in the brain of the teleost, Myoxocephalus scorpius.

Fluorescent histochemistry was carried out on the brain of the teleost Myoxocephalus scorpius to show the distribution of monoaminergic neurones and their projections. Posterior to the obex of the fourth ventricle, at the junction of the spinal chord and medulla, there is an unpaired dorsal nucleus of catecholaminergic cells. A second group of catecholaminergic perikarya are scattered lateral to the vagal and glossopharyngeal motor nuclei. Both groups of aminergic cells contribute to a tract which crosses the fourth ventricle at the obex and runs along the lateral wall of the medulla towards the diencephalon. At the level of the isthmus there is a lateral nucleus composed of large catecholaminergic cells with prominent fluorescent axons and its possible homology with the locus coeruleus is considered. Medially, in the same region a nucleus of serotonergic neurones lies between the paired tracts of the fasciculus longitudinalis medialis. In the diencephalon there are three paraventricular nuclei, the nuclei recessus posterioris and lateralis and the paraventricular organ pars anterior. Ventral to the lateral recess there is a further nucleus less closely associated with the ependyma. The distribution of fluorescent fibres is described and the dispositions of the aminergic nuclei compared to those of other teleosts.

Animals↗
PubMed1982

The survival of neonatal rat retinal ganglion cells in vitro is enhanced in the presence of appropriate parts of the brain.

The enzyme horseradish peroxidase (HRP) was injected into the visual centres of the brains of neonatal rats. Following dissociation of retinae into tissue culture, the ganglion cells could be identified by appropriate histochemical staining for HRP reaction product. Cultures were prepared of dissociated retinae from rats aged 2-6 days postnatal. After 3 h the cultures were fixed, and HRP-labelled cells visualized and counted. Estimates were made of the number of ganglion cells per retina at each age. Results indicated a loss of ganglion cells during the first few postnatal days. This loss paralleled that observed in vivo. It was further found the retinal ganglion cells died rapidly in vitro when cultured in a minimal medium. Only 50% of ganglion cells originally plated remained viable after 24 h. However, the survival rate could be increased to 100% by co-culturing the cells with diencephalon and mesencephalon; these contain the retinorecipient nuclei. Co-culturing with cerebellum did not result in such an enhanced survival rate. Ganglion cells could be maintained over longer periods of time by reinoculating the cultures with additional tissue containing diencephalon and mesencephalon. These results support the hypothesis that developing neurons require trophic factors from their target tissues in order to survive.

Animals↗
PubMed1989

Stereotactic interstitial irradiation of diencephalic tumors with iridium 192 and iodine 125: 10 years follow-up and comparison with other treatments.

The only possible treatment of non-removable tumors of the diencephalon or recurring tumors invading the diencephalon after partial resection or percutaneous radiotherapy is interstitial irradiation (Curie therapy). With the CT/MRI stereotactic method, biopsy for histological tumor classification can be performed and 125I or 192Ir implanted, provided the neuroimaging methods show the delimitation of the tumor, its diameter does not exceed 3 cm and, given the patient's condition, focal irradiation seems advisable. As of 31 August 1987, a total of 1883 cases had been stereotactically biopsied and interstitially irradiated. The indications and results are reported in 204 patients under 18 years of age with diencephalic and deep-seated astrocytomas, after a follow-up period of up to 10 years; the data were compared for tumor resection, percutaneous irradiation, and for interstitial irradiation. The latter proved to be the most effective treatment.

Adolescent↗
PubMed1989

The distribution of zinc in the forebrain and midbrain of the lizard Gekko gecko. A histochemical study.

The distribution of zinc in the forebrain and midbrain of the lizard Gekko gecko was studied with the recently modified Timm method. Areas with a high intensity of staining are almost exclusively found in the telencephalon, although also some structures in the diencephalon display notable staining. Cortical areas that stain heavily are the deep zone of the subcortical layer of the small-celled medial cortex, the longitudinal association bundle that encompasses the large-celled medial cortex, and the dorsal cortex. Of the subcortical areas, particularly the anterior septal nucleus shows a high intensity of staining. Moderate to dense Timm staining is further observed in the ventral part of the anterior lateral cortex, the lateral septal nucleus, the striatum, the amygdaloid complex, and the dorsal ventricular ridge. Staining in the diencephalon is primarily confined to the stria terminalis and the ventromedial hypothalamic nucleus, whereas in the midbrain weak staining is observed in the ventral tegmental area and the periventricular layers of the tectum and the tegmentum. The presence of zinc in the gekkonid brain is discussed in relation to connections and neurotransmitters as studied in same species. Moreover, similarities in pattern of staining for zinc in mammals and reptiles and possible evolutionary implications are mentioned.

Animals↗
PubMed1984

Acceleration of cerebral noradrenaline turnover after morphine withdrawal and its retardation by acute morphine administration in rats.

To clarify the effects of withdrawal from chronic morphine treatment on cerebral noradrenaline (NA) turnover, we have measured the alpha-methyl-p-tyrosine (alpha MT)-induced depletion of NA in five brain areas of male Wistar rats given morphine twice daily for 40 or 60 days. After the last morphine dose (50 or 70 mg/kg) the rats were withdrawn for 1, 2 or 4 days. In order to study the development of tolerance a challenge dose of 10 mg/kg of morphine was given to some of the rats. Withdrawal of morphine accelerated the alpha MT-induced NA depletion clearly in the hemispheres and the lower brain stem and slightly in the diencephalon. The acceleration was more pronounced in the brains of rats treated for 60 days than of those treated for 40 days. In the hemispheres the acceleration of NA depletion occurred at 1 and 2 days, in the diencephalon at 2 days, and in the lower brain stem at 2 and 4 days after morphine withdrawal. The most pronounced acceleration of NA depletion coincided with the maximum withdrawal-induced weight loss. The challenge dose of morphine clearly retarded the alpha MT-induced NA depletion in the hemispheres of control rats treated chronically with saline. This retardation was even more pronounced in rats withdrawn from chronic morphine treatment for 1 or 2 days. The challenge dose slightly accelerated the alpha MT-induced NA depletion in the lower brain stem of control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1978

Lewy bodies in cerebral cortex, report of three cases.

The histochemical and structural properties and the topographical distribution pattern of Lewy bodies in the cerebral cortex as well as in the brain stem and diencephalon were studied in three cases. The Lewy bodies in the cerebral cortex were found in the small or medium-sized neurons of the fifth and sixth layers, particularly in the anterior frontal, temporal, insular, and cingulate cortex, and showed minor differences in their histochemical and structural properties from typical Lewy bodies in the brain stem and diencephalon. By light microscopy they were more irregular in shape, less eosinophilic, less sharply demarcated, and did not have clear halos and central cores. From the ultrastructural aspect, the filaments in them did not radiate, but were arranged at random, and circular profiles were not associated in the central zone. This type of Lewy body was also distributed in the basal ganglia. A close relationship between Lewy bodies and monoamines in the cerebral cortex of our cases was not recognized. These three cases showed also concomitant senile changes, i.e., senile plaques and neurofibrillary tangles.

Aged↗
PubMed1979

d-Amphetamine-induced increase in catecholamine synthesis in the corpus striatum of the rat: persistence of the effect after tolerance.

The effect of d-amphetamine on in vivo catecholamine synthesis in four regions of rat brain was determined by measuring the accumulation of dopa after inhibiton of dopa decarboxylase. In doses up to 2.5 mg/kg, d-amphetamine caused dose-dependent increases in striatal dopa accumulation to a maximum of 280% of control; further increases in dose resulted in smaller effects until 10 mg/kg d-amphetamine was not significantly different from control. d-Amphetamine did not alter dopa accumulation in telencephalon, in diencephalon-mesencephalon, or in pons-medulla oblongata. d-Amphetamine did not affect either dopamine levels in striatum or NE levels in pons-medulla oblongata; at high doses, d-amphetamine did reduce norepinephrine levels in telencephalon and in diencephalon-mesencephalon. Daily administration of pre-session but not of post-session d-amphetamine produced tolerance to the effects of d-amphetamine on milk consumption in rats. The ability of d-amphetamine to increase striatal catecholamine synthesis was not altered by the development of tolerance to d-amphetamine. These results suggest that tolerance to d-amphetamine is not related to its effect on catecholamine synthesis but instead occurs via changes in aspects of catecholamine metabolism other than synthesis via change in catecholamine release, reuptake, or receptor sensitivity, or via changes in non-catecholaminergic mechanisms.

Animals↗
PubMed2004

Prolonged ethanol ingestion increases renal AQP2 and AQP3 expression in adult rats and in their offspring.

This study evaluates the effect of prolonged ethanol ingestion on the renal ability to concentrate urine. Suckling Wistar rats born to mothers given ethanol before and during gestation and suckling periods (ethanol-exposed offspring) were used and the results were compared with those obtained from offspring of dams given diets containing no ethanol. Comparisons were also made between progenitors with or without prolonged ethanol ingestion. Body and kidney weights; arginine-vasopressin (AVP) and aldosterone plasma levels; plasma, urine and renal papillary osmolality; urine outflow; kidney AQP2, AQP3 and AQP4 expression and diencephalon AVP mRNA expression were determined. As compared with control offspring, the ethanol-exposed offspring present i) lower body and kidney weights; ii) lower urine outflow; iii) higher renal AQP2 and AQP3 mRNA; iv) higher renal AQP2 protein content and v) higher urine and renal papillary osmolality. These changes were also observed in the ethanol-treated progenitors, although they were of smaller magnitude. Plasma osmolality, renal AQP4 mRNA, AVP plasma levels and diencephalon AVP mRNA expression were not affected by the ethanol treatment. Plasma levels of aldosterone were only significantly increased in the ethanol-exposed suckling rats. It is concluded that maternal ethanol ingestion before and during gestation and suckling periods affects the renal function of the offspring, up-regulating renal AQP2 expression by an AVP-independent mechanism. Ethanol-treated progenitors manifest similar renal changes, although of lesser magnitude than the offspring.

Aldosterone↗
PubMed1999

Postembryonic neural proliferation in the zebrafish forebrain and its relationship to prosomeric domains.

Large gaps of knowledge exist regarding postembryonic brain morphogenesis of the zebrafish Danio rerio (Cyprinidae, Teleostei). The zebrafish represents together with the frog (Xenopus), chick and mouse--one of four major models for the genetic study of early brain development. Here, we used normal silver-stained Bodian material and immunohistochemical material stained with a monoclonal antibody against the proliferating cell nuclear antigen (PCNA, cyclin) to study the morphogenetic appearance and location of proliferation zones of the zebrafish brain between day 1 and day 10, focussing on the forebrain at day 5 postfertilization. Our results directly demonstrate that the dorsal telencephalic proliferation zone (i.e. the pallium) extends--consistent with the process of eversion--some distance laterally on top of the telencephalon. The subpallial telencephalic proliferation consists of dorsal and ventral zones. The preoptic region also includes dorsal and ventral proliferation zones. In the diencephalon proper, separate proliferation zones are present in the habenula, and in the periventricular cell masses of the dorsal thalamus, the ventral thalamus, and the pretectum. More ventrocaudally, the latter three massive proliferation zones appear to be replaced each by thinner, but distinct proliferation zones. Two of them represent ventrocaudal continuations of the dorsal and ventral thalamus and lie in the region referred to as the posterior tubercular area in adult teleostean neuroanatomy. The third lies in the region of the nucleus of the medial longitudinal fascicle. In addition, several hypothalamic proliferation zones are present. The data for the diencephalon are largely in agreement with the neuromeric model of brain organization of Puelles and Rubenstein (1993), which is mostly based on amniote data. Generally, the understanding of the prosomeric origin of teleostean prosencephalic cell masses may be regarded as pivotal for their comparative interpretation.

Animals↗
PubMed1980

Ontogeny of muscarinic receptors in rat brain.

The ontogeny of muscarinic acetylcholine receptors in the rat brain has been examined using the radioligands, [3H]N-methylscopolamine, [3H]propylbenzilylcholine and [3H]oxotremorine-M. In the 3 regions of the brain selected for study, the cerebral cortex, the diencephalon and the medulla-pons, the receptors develop at different rates. The most rapid development takes place in the medulla with considerably slower maturation in the diencephalon and cerebral cortex. In the cortex, the agonist binding properties of the muscarinic receptors vary during development. There appears to be a 6--7 day lag in the appearance of high affinity sites following formation of low affinity sites.

Aging↗
PubMed1982

Diencephalic projections from the pontine reticular formation: autoradiographic studies in the cat.

Ascending projections to the diencephalon from the pontine reticular formation were studied in the cat by autoradiographic techniques. Projections from both rostral and caudal pontine regions ascend to the caudal diencephalon and divide into two components; a dorsal leaf terminates primarily in the thalamic intralaminar complex and a ventral leaf terminates in the subthalamic region. The relative densities of the two terminal regions vary with the injection site. Fibers originating in the caudal pons (nucleus reticularis pontis caudalis) terminate relatively heavily in the intralaminar nuclei of the dorsal thalamus, particularly the centre median, central lateral, central dorsal and paracentral nuclei, and also the dorsal medial nucleus. Relatively sparse termination occurs in the subthalamic region. In contrast, fibers from the rostral pons (nucleus reticularis pontis oralis) terminate relatively heavily in the subthalamic region, including the zona incerta, the fields of Forel, the ventral part of the thalamic reticular complex, and the lateral hypothalamus. Relatively sparse termination occurs in the dorsal thalamus, but includes the centre median, parafascicular, central lateral, paracentral and dorsal medial nuclei. These data are discussed with regard to reticular control of forebrain activity and the role of the classic dorsal and ventral components of ascending reticular projections.

Afferent Pathways↗
PubMed1982

The effects of intracerebroventricular administration of 5,6-dihydroxytryptamine to neonatal rats.

5,6-Dihydroxytryptamine was administered intracerebroventricularly to neonatal rats on days 3 and 6 (25, 50, 75 or 100 micrograms) or on day 12 (50, 75 or 100 micrograms) after birth. Administration on days 3 and 6 increased serotonin (5-HT) in the diencephalon, decreased it in the telencephalon and produced variable results in the brainstem. The dose of 100 micrograms eliminated the peak in locomotor activity that normally occurs at day 15. Administration on day 12 produced increased 5-HT levels in the diencephalon and the brainstem. The dose of 100 micrograms delayed the decrease in activity after the peak. Administration on days 3 and 6 or on day 12 produced non-specific damage throughout the brain, although dopamine levels were normal. The behavioral effects did not correspond with the neurochemical effects and probably were due to the pronounced non-specific effects of the treatment.

5,6-Dihydroxytryptamine↗
PubMed1988

Ascending and descending projections of the nucleus reticularis gigantocellularis in the cat demonstrated by the anterograde neural tracer, Phaseolus vulgaris leucoagglutinin (PHA-L).

Ascending and descending projections of the nucleus reticularis gigantocellularis (NRGc) were studied in the cat by the anterograde tracer, Phaseolus vulgaris leucoagglutinin. Ascending fibers from the left or the right NRGc coursed through the bilateral medial reticular formation and some of them reached the diencephalon. In the brainstem, PHA-L-labeled fibers and their terminals were observed in the medial reticular formation, the cranial motor nuclei (III, IV, V, VI, VII, XII), the vestibular complex, the LC complex, the raphe nuclei, the periaqueductal gray, the red nucleus, the Edinger-Westphal nucleus and the interstitial nucleus of Cajal. In the diencephalon, they were observed in the dorsal thalamus and the hypothalamic regions. In the caudal medulla, labeled fibers and their terminals were observed in the nucleus prepositus hypoglossi, the nucleus intercalatus and the inferior olive. Descending axons from the NRGc coursed bilaterally through the ventral and ventrolateral funiculi as far caudal as the upper thoracic cord. Single axon collaterals arising from the descending axons gave off terminal fibers to the left or the right gray matter. Their terminals were located in laminae V-X, mainly in laminae VII and VIII. In lamina IX, they were distributed mainly in the medial portion. A few fibers originating from the descending axons ipsilateral to the PHA-L injection side coursed through the anterior or posterior commissure, and ended in laminae VI, VII and VIII. The functional implications of these findings are discussed in relation to the behavioral state control and the generalized motor inhibition.

Afferent Pathways↗
PubMed1990

Asymmetry in diencephalic monoamine metabolism is related to side of ovulation in a reptile.

The green anole lizard (Anolis carolinensis), like humans and other higher primates, alternates ovulation between left and right ovaries. To test the possible role of hypothalamic function in ovarian asymmetry, we measured levels of 3 major monoamine neurotransmitters (norepinephrine; dopamine; serotonin) and their metabolites in microdissected left and right diencephalon from lizards during the first cycle of ovulation in the spring. All of the metabolite/parent neurotransmitter ratios were significantly higher on the side of the diencephalon ipsilateral to the quiescent ovary than on the side of the maturing ovary. Simultaneous ovarian and brain asymmetry suggests direct communication between the ovary and brain, presumably through the ovarian innervation.

Animals↗
PubMed1983

Trajectories of axons in ectopic VIIIth nerves.

Transplantation of the acousticolateral placode to the evacuated eye position in embryos of the frog Rana pipiens has been used to force axons of the VIIIth cranial nerve to penetrate the diencephalon. These ectopic axons establish a growth trajectory that is strikingly similar to their normal growth trajectory within the medulla oblongata despite the fact that no other axons within the diencephalon normally follow this route. The result is discussed in terms of the "blueprint" and substrates pathway hypotheses which have been advanced to explain the initial development of axon tracts within the central nervous system.

Animals↗
PubMed1977

Types of hypoxic and posthypoxic delta activity in animals and man.

1. Two types of hypoxic delta activity were observed in ECoG records of dogs subjected to exsanguination, sudden cardiac arrest resulting from ventricular fibrillation or mechanical asphyxiation, as well as during post-hypoxic recovery. They were polymorphous delta activity (PDA) and "standard slow complexes" (SSCs). 2. These two types of delta activity were found to differ from each other as to the shape of the potentials; their amplitude in monopolar and bipolar leads; the cortical areas in which the activity exhibited the highest amplitude; the degree of manifestation in the cortex and subcortical structures; their relation to activating influences; their dependence on the stage and character of hypoxia. 3. Analysis of EEG records of patients during and after hypoxia made it possible to distinguish both PDA and a type of delta activity similar to the SSCs observed in experimental animals. 4. It is suggested that the appearance of SSCs is determined by the activity of a pacemaker situated in the diencephalon and responding to pO2 changes, and that the mechanism of SSC generation is closer to that of monorhythmic, bilataerally synchronous delta waves observed in primary irritative or epileptogenic processes in the diencephalon.

Animals↗