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 937 records · Page 52Linked to original sources
PubMed2003

Synthesis and characterization of iodine-123 labeled 2beta-carbomethoxy-3beta-(4'-((Z)-2-iodoethenyl)phenyl)nortropane. A ligand for in vivo imaging of serotonin transporters by single-photon-emission tomography.

2beta-Carbomethoxy-3beta-(4'-((Z)-2-iodoethenyl)phenyl)nortropane (ZIENT) (6) and 2beta-carbomethoxy-3beta-(4'-((E)-2-iodoethenyl)phenyl)nortropane (EIENT) (10) were prepared and evaluated in vitro and in vivo for serotonin transporter (SERT) selectivity and specificity. High specific activity [(123)I]ZIENT and [(123)I]EIENT were synthesized in 45% (n = 5) and 42% (n = 4) radiochemical yield (decay-corrected to end of bombardment (EOB)), respectively, by preparation of the precursor carbomethoxy-3beta-(4'-((Z)-2-trimethylstannylethenyl)phenyl)nortropane (7) and 2beta-carbomethoxy-3beta-(4'-((E)-2-tributylstannylethenyl)phenyl)nortropane (9), respectively, followed by treatment with no carrier-added sodium [(123)I]iodide and hydrogen peroxide in ethanolic HCl. Competition binding in cells stably expressing the transfected human SERT, dopamine transporter (DAT), and norepinephrine transporter (NET) using [(3)H]citalopram, [(3)H]WIN 35,428, and [(3)H]nisoxetine, respectively, demonstrated the following order of SERT affinity (K(i) in nM): ZIENT (0.05) > nor-CIT (0.12) >> EIENT (1.15) > fluvoxamine (1.46). The affinity of ZIENT and EIENT for DAT was 69 and 1.6-fold lower, respectively, than for SERT. In vivo biodistribution and blocking studies were performed in male rats and demonstrated that the brain uptake of [(123)I]ZIENT was selective and specific for SERT-rich regions (hypothalamus, striatum, pons, and prefrontal cortex). SPECT brain imaging studies in monkeys demonstrated high [(123)I]ZIENT uptake in the diencephalon, which resulted in diencephalon-to-cerebellum ratios of 2.12 at 190 min. [(123)I]ZIENT uptake in the diencephalon achieved transient equilibrium at 157 min. In a displacement experiment of [(123)I]ZIENT in a cynomolgus monkey, radioactivity was reduced by 39% in the diencephalon at 101 min following injection of citalopram. The high specific activity one-step radiolabeling preparation and high selectivity of [(123)I]ZIENT for SERT support its candidacy as a radioligand for mapping brain SERT sites.

Animals↗
PubMed1998

A differential response of diffuse brain injury on the concentrations of endothelin and nitric oxide in the plasma and brain regions in rats.

In the present study, we hypothesized that acute diffuse brain injury (DBI) in rats would produce an increase in endothelin-1 (ET-1), a potent vasoconstrictor, and/or nitric oxide (NO), a potent vasodilator, in plasma and brain areas in rats. DBI was induced in anesthetized male Sprague-Dawley rats (350-400 g) using a 350 g weight dropped from 1 meter height impact through a device designed by Marmarou et al., 1994. Blood plasma and brain tissue (cerebral cortex, diencephalon and brain stem) samples were collected for estimation of ET-1 and NO at zero or 6 h from rats (n = 6) subjected to DBI as well as control rats (n = 6), i.e., not subjected to DBI. In a separate group of animals, cerebral blood flow (CBF) was recorded at 0, 5, 10, 15, 30, 60, 120, 240 and 360 min after induction of DBI or sham-DBI. Acute DBI produced a significant decrease in CBF at 120 min after induction of DBI. Plasma levels of ET-1 was found to be significantly increased (from 0.89 +/- 0.09 to 2.09 +/- 0.29 pg ml-1), at 6 h following DBI. DBI produced a significant decrease in the levels of ET-1 in diencephalon (from 70.97 +/- 9.47 to 57.64 +/- 2.65 pg g-1). In contrast to ET-1, DBI produced a significant increase in the concentrations of NO in the diencephalon, cerebral cortex and brain stem at 6 h post DBI. It appears that DBI-induced increase in the levels of NO in brain regions which might be down regulating the synthesis of ET-1 in diencephalon. It is concluded that ET and NO homeostatic mechanisms may play a role in the regional and vascular responses associated with acute DBI.

Analysis of Variance↗
PubMed2005

Adiponectin gene is expressed in multiple tissues in the chicken: food deprivation influences adiponectin messenger ribonucleic acid expression.

Adiponectin is a cytokine hormone originally found to be secreted exclusively by white adipose tissue. However, recent evidences suggest that adiponectin is also produced in brown adipose tissue and skeletal muscle. The present study investigated the expression of adiponectin mRNA in various tissues in the chicken. We also studied the effect of food deprivation on adiponectin gene expression in adipose tissue, liver, anterior pituitary gland, and diencephalon in the chicken. The open reading frame of chicken adiponectin cDNA consists of 735 nucleotides that were 65-68% homologous to various mammalian adiponectin cDNAs. The deduced amino acid sequence of chicken adiponectin contains 22 glycine-X-Y repeats (in which X and Y represent any amino acid) at the N-terminal end as found in the mammalian adiponectin. By RT-PCR and Northern analysis, we detected chicken adiponectin mRNA transcript in adipose tissue, liver, anterior pituitary gland, diencephalon, skeletal muscle, liver, kidney, ovary, and spleen but not in blood. Adiponectin mRNA expression in various tissues was quantitated using real-time quantitative PCR and found to be the highest in adipose tissue, followed by liver, anterior pituitary, diencephalon, kidney, and skeletal muscle. We also found that adiponectin mRNA quantity was significantly decreased after a 48-h food deprivation in adipose tissue, liver, and anterior pituitary gland but not in diencephalon. Our results provide novel evidence that, unlike mammals, adiponectin gene is expressed in several tissues in the chicken and that its expression is influenced by food deprivation.

Adiponectin↗
PubMed2004

Foxd1 is required for proper formation of the optic chiasm.

In animals with binocular vision, retinal ganglion cell (RGC) axons from each eye sort in the developing ventral diencephalon to project to ipsi- or contralateral targets, thereby forming the optic chiasm. Ipsilaterally projecting axons arise from the ventrotemporal (VT) retina and contralaterally projecting axons primarily from the other retinal quadrants. The winged helix transcription factor Foxd1 (previously known as BF-2, Brain Factor 2) is expressed in VT retina, as well as in the ventral diencephalon during the formation of the optic chiasm. We report here that in embryos lacking Foxd1, both retinal development and chiasm morphogenesis are disrupted. In the Foxd1 deficient retina, proteins designating the ipsilateral projection, such as Zic2 and EphB1, are missing, and the domain of Foxg1 (BF-1) expands from nasal retina into the VT crescent. In retina-chiasm co-cultures, VT RGCs from Foxd1 deficient retina are not repulsed by chiasm cells, and in vivo many VT RGCs aberrantly project contralaterally. However, even though the ipsilateral program is lost in the retina, a larger than normal uncrossed component develops in Foxd1 deficient embryos. Chiasm defects include axon stalling in the chiasm and a reduction in the total number of RGCs projecting to the optic tract. In addition, in the Foxd1 deficient ventral diencephalon, Foxg1 invades the Foxd1 domain, Zic2 and Islet1 expression are minimized, and Slit2 prematurely expands, changes that could contribute to axon projection errors. Thus, Foxd1 plays a dual role in the establishment of the binocular visual pathways: first, in specification of the VT retina, acting upstream of proteins directing the ipsilateral pathway; and second, in the patterning of the developing ventral diencephalon where the optic chiasm forms.

Animals↗
PubMed1990

The development of a simple scaffold of axon tracts in the brain of the embryonic zebrafish, Brachydanio rerio.

We have examined neuronal differentiation and the formation of axon tracts in the embryonic forebrain and midbrain of the zebrafish, between 1 and 2 days postfertilisation. Axons were visualised with three techniques; immunocytochemistry (using HNK-1 and antiacetylated tubulin antibodies) and horseradish peroxidase (HRP) labelling in whole-mounted brains, and transmission electron microscopy. Differentiation was monitored by histochemical staining for acetylcholinesterase (AChE). These independent methods demonstrated that a simple grid of tracts and commissures forms the initial axon scaffold of the brain. At 1 day, the olfactory nerve, four commissures, their associated tracts and three other non-commissural tracts are present. By 2 days, these tracts and commissures have all greatly enlarged and, in addition, the optic nerve and tract, and three new commissures and their associated tracts have been added. Small applications of HRP at various sites revealed the origins and projections of some of these earliest axons. Retrogradely labelled cell bodies originated from regions that were also positive for AChE activity. At 1 day, HRP-labelled axons were traced: (1) from the olfactory placode through the olfactory nerve to the dorsal telencephalon; (2) from the telencephalon into the tract of the anterior commissure and also to the postoptic region of the diencephalon; (3) from the hindbrain through the ventral midbrain and diencephalon to the postoptic commissure; (4) from the dorsal diencephalon (in or near the epiphysis) to the tract of the postoptic commissure; (5) from ventral and rostral midbrain through the posterior commissure. Three new projections were demonstrated at 2 days: (1) from the retina through the tract of the postoptic commissure to the tectum; (2) from the telencephalon to the contralateral diencephalon; and (3) from the telencephalon to the ventral flexure. These results show that at 1 day, the zebrafish brain is impressively simple, with a few small, well-separated tracts but by 2 days the brain is already considerably more complex. Most of the additional axons added onto pre-existent tracts rather than pioneered new ones supporting the notion that other axons play a crucial role in the guidance of early central nervous system (CNS) axons.

Acetylcholinesterase↗
PubMed1985

Effects of idebenone (CV-2619) on metabolism of monoamines, especially serotonin, in the brain of normal rats and rats with cerebral ischemia.

The effects of 6-(10-hydroxydecyl)-2,3-dimethoxy-5-methyl-1,4-benzoquinone (idebenone, CV-2619) on the contents, turnover, release and uptake of monoamines, especially serotonin (5-HT), in various brain regions of Wistar rats were studied in vivo and in vitro. In normal rats, an intraperitoneal (i.p.) dose of 100 mg/kg of CV-2619 had no significant effect on the levels of norepinephrine (NE), dopamine (DA) and their metabolites, and 5-HT in the brain regions examined, but it increased the levels of 5-hydroxyindole-3-acetic acid (5-HIAA), the main metabolite of 5-HT, in many brain regions. In rats with cerebral ischemia, a low dose (10 mg/kg, i.p.) of CV-2619 normalized the decreased levels of 5-HIAA in the cerebral cortex, hippocampus, diencephalon and brain stem. A 5-HT biosynthesis inhibitor, DL-p-chlorophenylalanine (PCPA, 150 mg/kg, i.p.), decreased the levels of 5-HT in all brain regions to one-third of the control levels 24 hr after administration in normal rats. CV-2619 (10, 30 or 100 mg/kg, i.p.), administered 24 hr after the treatment with PCPA, accelerated the PCPA-induced 5-HT decreases in the hippocampus, diencephalon and brain stem in a dose-dependent manner. In vitro CV-2619, like p-chloroamphetamine (PCA), stimulated 5-HT release from slices of the hippocampus and diencephalon. CV-2619 slightly inhibited and PCA markedly inhibited 5-HT uptake into hippocampal slices. The mechanism of the 5-HT releasing action of CV-2619 in hippocampal slices seems to be mediated through endogenous calcium. These results suggest that CV-2619 has an enhancing effect on the turnover of 5-HT in the hippocampus, diencephalon and brain stem of rats.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2004

Morphogenesis of the rat forebrain.

BACKGROUND AND PURPOSE: Developmental process that leads to final forebrain shaping is a result of complex histogenetic and morphogenetic events. Comprehensions about brain development are based on observations carried out on onthogenetic successive stages. Microscopic analysis of brain together with analysis of serial sections gives information about shape the of some forebrain parts and basic relations between them. The aim of this study was to analyse morphogenesis in the earliest stages of rat's forebrain development. MATERIAL AND METHODS: Rat brains used in this study were obtained from Fisher inbred rats with accurately timed pregnancies. The investigation was carried out on serial frontal sections of rat embryonic heads from the 12th (E12) to the 16th (E16) day of gestation. Gestation was considered to have begun early in the morning when sperm was found in the vaginal smear. Histological paraffin and plastic sections were systematically inspected with regard to morphogenetic changes of the forebrain parts telencephalon and diencephalon. RESULTS: E12: neural tube is completely closed in its cranial part. Rostral part of forebrain shows telencephalons vesicles origins as slightly paired enlargements of neuroepithelial wall. Between telencephalic vesicles origin and in direction to caudal there is an origin of diencephalon. E13: rostral part of forebrain shows well expressed and divided areas of telencephalons vesicles as basal, basolateral, dorsal and medial telencephalon. Central area between paired vesicles is a telencephalon impar. In diencephalon optic vesicles appeared. Epithalamus, thalamus and hypothalamus origins are slight enlargements of its neuroepithelial wall. E14: telencephalic vesicles spread above telencephalon impar into rostral direction and above diencephalon in rostrodorsal direction. Their basolateral parts of are very thickened and become folded. Sulcus telodiencephalicus appears. E15: the main event is the appearance of the origins of plexus choroideus in the area of telencephalon impar as fingerlike processes. E16: all forebrain parts, especially telencephalic vesicles-origin of brain hemispheres and processes of plexus choroideus, are progressively growing and shaping. CONCLUSIONS: Our morphologic analysis describes significant morphogenetic changes in the forebrain shape. The forebrain changes from a relatively simple tubular structure with thin walls surrounding a large ventricular system to a thick-walled brain with a highly convoluted but reduced ventricular system.

Animals↗
PubMed1984

A reevaluation of midbrain and diencephalic projections to the inferior olive in rat with particular reference to the rubro-olivary pathway.

Projections from the midbrain and caudal diencephalon to the inferior olivary nucleus (ION) in the rat were investigated by using anterograde and retrograde tracing techniques. Particular attention was directed to studying the projection from the red nucleus (RN) to the ION. Tritiated leucine was stereotaxically injected into the RN in six animals. The injection sites and the portion of the medulla containing the ION were processed for autoradiography. In three cases, the injections were largely confined to the RN. In these instances, no terminal labeling was noted in the ION. In the other three animals, the injections spread beyond the RN to include, in one or another of the rats, such areas as the mesencephalic reticular formation (MRF) between the RN and the periaqueductal gray (PAG), the region around the fasciculus retroflexus (FR), the prerubral area, the MRF dorsolateral to the RN, or the region dorsal to the medial geniculate body. In these animals, terminal labeling was observed ipsilaterally in the ION, chiefly in the caudal one-half of the medial accessory olive and in the dorsal lamella and lateral bend of the principal olive. Retrograde transport of lectin-conjugated horseradish peroxidase (WGA-HRP) or the fluorescent dye fast blue (FB), injected into the ION, was used to localize regions in the midbrain and caudal diencephalon containing neurons which project to the inferior olive. Following WGA-HRP injections into the ION, retrogradely labeled neurons were found in the ipsilateral ventral PAG, the MRF between the PAG and the RN, the MRF dorsolateral to the RN, and the area dorsal to the medial geniculate body. Large numbers of heavily labeled neurons were found in the area surrounding the FR. No labeled cells were noted in the RN or the nucleus of Darkschewitsch (ND). Subsequent to FB injections into the ION, fluorescent neurons were observed in the same regions which contained HRP-labeled neurons in the experiments using the enzyme as a tracer. Additionally, very small numbers of FB-labeled neurons were found in the RN and the ND. These results indicate that, in the rat, descending input from the midbrain and caudal diencephalon to the ION arises chiefly from a medially located column of neurons extending from the level of the rostral RN to the region of the FR. Little, if any, input to the ION is derived from the ND or RN in this species, unlike the cat, in which a substantial projection to the ION arises from the ND and the RN.

Amidines↗
PubMed1989

Subcortical projections to the pontine nuclei in the cat.

In a systematic attempt to trace all projections from the brainstem and diencephalon to the pontine nuclei of the cat, implantations and injections of horseradish peroxidase-wheat germ agglutinin (HRP-WGA) or Fluoro-Gold were placed in the pontine nuclei of 21 cats. In most of the cases there was no evidence of spread of tracer outside the pontine nuclei. Retrogradely labeled cells in the brainstem and diencephalon were carefully mapped and counted. The number labeled cells in the brainstem and diencephalon ranged from 24 in cases with very small implantations to 3,490 in cases with large injections in the pontine nuclei (counts from every fifth section). The labeled cells are located bilaterally with an ipsilateral preponderance. After large injections, 25-38% of the labeled cells were located in the brainstem reticular formation, 10-16% in the pretectal nuclei, 10-15% in the hypothalamus, 7-9% in the zona incerta, 3-9% in the fields of Forel, 4-5% in the nucleus locus coeruleus, 3-5% in the ventral lateral geniculate body, 2-4% in the superior colliculus, 3% in the periaqueductal gray, and 14-15% in other parts of the brainstem. Judging from cases with small tracer deposits entirely confined to the pontine nuclei, there appear to be two types of subcortical inputs: Projections from the reticular formation, the nucleus locus coeruleus, the periaqueductal gray, and the raphe nuclei are widespread, presumably reaching all parts of the pontine nuclei, while projections from a diversity of other sources are localized, reaching limited parts of the pontine nuclei only or predominantly.

Animals↗
PubMed1995

Systemic uptake inhibition decreases serotonin release via somatodendritic autoreceptor activation.

In vivo microdialysis was used to examine the effects of peripheral uptake inhibition on extracellular serotonin (5-HT). Previous results from this lab indicated that systemic fluoxetine caused a decrease in 5-HT when terminal uptake was inhibited by local infusion of the uptake blocker. We hypothesized that the decrease in 5-HT levels in the terminal region was due to an increase in 5-HT in the vicinity of the inhibitory somatodendritic autoreceptors in the dorsal raphe nucleus (DRN). To test this prediction, rats were implanted with probes in both the basal diencephalon (a nerve terminal region) and the DRN (the cell body region). Fluoxetine (10 mg/kg i.p.) increased extracellular 5-HT, in a depolarization-dependent manner, by approximately 140% in both areas. In a separate experiment, fluoxetine was infused into the diencephalon overnight to block nerve terminal uptake sites. This pretreatment caused an eight- to 10-fold increase in 5-HT levels. Subsequent systemic fluoxetine, sertraline, or paroxetine, produced a 50% decrease in extracellular 5-HT in the diencephalon, presumably due to activation of the 5-HT1A somatodendritic autoreceptors. Consistent with this hypothesis, systemic administration of the 5-HT1 antagonists spiperone, penbutolol, or WAY100135 reversed the fluoxetine-induced decrease in 5-HT to approximately 85% of the pre-fluoxetine baseline levels. Likewise, pretreatment with penbutolol, but not selective beta-adrenergic antagonists, blocked the fluoxetine-induced decrease in release. These findings suggest that the ability of acute systemic 5-HT uptake inhibition to elevate nerve terminal 5-HT is limited by autoreceptor activation following elevation of 5-HT in the DRN.

Animals↗
PubMed1998

Neuroanatomical distribution and variations across the reproductive cycle of aromatase activity and aromatase-immunoreactive cells in the pied flycatcher (Ficedula hypoleuca).

The anatomical distribution and seasonal variations in aromatase activity and in the number of aromatase-immunoreactive cells were studied in the brain of free-living male pied flycatchers (Ficedula hypoleuca). A high aromatase activity was detected in the telencephalon and diencephalon but low to negligible levels were present in the optic lobes, cerebellum, and brain stem. In the diencephalon, most aromatase-immunoreactive cells were confined to three nuclei implicated in the control of reproductive behaviors: the medial preoptic nucleus, the nucleus of the stria terminalis, and the ventromedial nucleus of the hypothalamus. In the telencephalon, the immunopositive cells were clustered in the medial part of the neostriatum and in the hippocampus as previously described in another songbird species, the zebra finch. No immunoreactive cells could be observed in the song control nuclei. A marked drop in aromatase activity was detected in the anterior and posterior diencephalon in the early summer when the behavior of the birds had switched from defending a territory to helping the female in feeding the nestlings. This enzymatic change is presumably controlled by the drop in plasma testosterone levels observed at that stage of the reproductive cycle. No change in enzyme activity, however, was seen at that time in other brain areas. The number of aromatase-immunoreactive cells also decreased at that time in the caudal part of the medial preoptic nucleus but not in the ventromedial nucleus of the hypothalamus (an increase was even observed), suggesting that differential mechanisms control the enzyme concentration and enzyme activity in the hypothalamus. Taken together, these data suggest that changes in diencephalic aromatase activity contribute to the control of seasonal variations in reproductive behavior of male pied flycatchers but the role of the telencephalic aromatase in the control of behavior remains unclear at present.

Animals↗
PubMed1994

Regional changes in amino acid levels of the neonate rat brain during anoxia and recovery.

The aim of this study was to compare the changes in amino acids (alanine, aspartate, GABA, glutamate, glutamine, glycine, serine taurine) that are produced in different regions of the neonate brain (telencephalon, diencephalon cerebellum, brain stem) following a survivable period of anoxia and after the re-establishment of air respiration. Anoxia provoked different responses in the different regions. The changes during the anoxic period were as follows. In the brain stem there was a decrease in aspartate, in the telencephalon there was a significant increase in GABA and alanine and a decrease in aspartate, in the diencephalon, glutamate and GABA increased, and in the cerebellum, glycine and alanine levels were enhanced. The changes during recovery were even more dissimilar. Here the greatest shifts were seen in the brain stem with increases in glutamine, GABA, aspartate, glycine, serine, alanine, and taurine. In the telemcephalon glutamate fell and alanine increased, in the diencephalon GABA increased, and in the cerebellum, glutamate fell while glycine and alanine increased. In none of the major brain regions did the pattern of changes in neurotransmitters correspond to that seen in anoxic tolerant species.

Amino Acids↗
PubMed2002

Differential responses of temporal and nasal retinal neurites to regional-specific cues in the mouse retinofugal pathway.

Retinal explants of mouse embryos were cultured together with explants of different regions in the retinofugal pathway in order to investigate whether ventral temporal (VT) and dorsal nasal (DN) retinal neurites showed differential responses to regional-specific cues in the pathway. In the presence of the chiasm, biased outgrowth of retinal neurites was found in explants of both retinal regions, which was accompanied by a reduction in total neurite growth in the VT but not the DN retina. Such differential responses to the diffusible negative influence were also observed when explants of two retinal origins were cocultured with the ventral diencephalon, but were not found with the dorsal diencephalon that contains targets of the optic axons. Indeed, extensive neurite invasion was found in the dorsal diencephalic explants and this ingrowth was more prominent for VT than DN neurites, showing a difference in axons from a distinct position in the retina to contact-mediated stimulatory activity within the target nuclei. We conclude that neurites from different regions of the retina show differential responses to the regional-specific cues in the diencephalon. These cues exist in both diffusible and contact-mediated forms that may shape the characteristic course and organization of retinal axons in decision regions of the optic pathway and the visual targets.

Animals↗
PubMed1976

Regional changes in monoamine content and uptake of the rat brain during postnatal development.

Regional norepinephrine (NE), dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) contents in the developing rat brain were estimated. The rate of increase in NE content was the highest in diencephalon, followed by the lower brain stem, limbic-striatum, neocortex and cerebellum. With postnatal aging, DA concentration increased markedly in limbic-striatum, slightly in the neocortex and negligibly in other regions. In each region except cerebellum, 5-HT content increased gradually but the rate of increase in diencephalon was relatively high. Comparison of the kinetics of high affinity uptake of L-[3H]NE and [3H]5-HT between the neonatal and the adult brain indicated that Km values of L-[3H]NE and [3H]5-HT uptake were 2.9 X 10(-7) M and 1.7 X 10(-7) M respectively in neocortex, diencephalon and lower brain stem and 4.3 X 10(-7) M and 2.3 X 10(-7) M in limbic-striatum in the neonate as well as in the adult. Vmax values of both amines uptake differed regionally and the values in the neonate were lower than those in the adult in all regions. Limbic-striatum showed a higher Vmax value than other regions in uptake of both amines. These results suggested that innervation of monoaminergic neurons in the brain progressed with increasing age, that projections of both NE and 5-HT neurons were relatively high into hypothalamus and limbic-striatum and that DA neuron projections concentrated at striatum. Although the brain, except for limbic-striatum, showed neither regional nor developmental differences in affinity of L-[3H]NE and [3H]5-HT to synaptosomes, the density of nerve terminal of both monoaminergic neurons increased in all regions of the brain during postnatal development. In limbic-striatum, higher Km and Vmax values of both amines, uptake suggest the existence of both amines' uptake into DA terminal to some extent.

Animals↗
PubMed1980

Differences in the collateralization of neuronal projections from the dorsal column nuclei and lateral cervical nucleus to the thalamus and tectum in the cat: an anatomical study using two different double-labeling techniques.

The dorsal column nuclei (DCN) and the lateral cervical nucleus (LCN) project to the diencephalon and tectum. In order to determine which neurons project to these targets and whether any of them have collateral projections, the double-retrograde labeling techniques developed by Hayes and Rustioni and Kuypers et al. were used. Both strategies produced similar results. Within DCN, neurons which projected to the diencephalon were located differently and had a different morphology than those which projected to the tectum. The diencephalic-projecting neurons, which were preferentially located within the middle part of the DCN complex were mainly large (> 15 micrometer diameter) and round. The tectal-projecting neurons, often located along the edges of the gracile and cuneate nuclei or between them, were most often found outside of the middle parts of the DCN complex (i.e. predominantly rostrally and frequently also caudally). These tectal-projecting neurons varied in size and were usually oval or fusiform in shape. In contrast to DCN, neurons in LCN which projected either to the tectum or diencephalon did not differ morphologically and in both groups were of various sizes and shapes. They were intermixed haphazardly, predominantly within the lateral two-thirds of the nucleus. In addition, another class of neurons, constituting more than 40% of the labeled population in some experiments, had collateral projections to both terminal targets. These double-labeled neurons were haphazardly mixed with other labeled neurons.

Animals↗
PubMed1988

Characterization of thyrotropin-releasing hormone in the central nervous system of African lungfish.

Central administration of thyrotropin-releasing hormone (TRH) produces potent effects on various physiological parameters, such as arousal, respiration, and cardiovascular function, in several species. As part of an investigation into the evolution of this tripeptide as a central modulator of these parameters, we examined its distribution in the central nervous system of the African lungfish (Protopterus). Lungfish brains were dissected into three regions: telencephalon, diencephalon, and medulla. Each region was assayed for TRH by radioimmunoassay and for norepinephrine, dopamine, and serotonin by HPLC/electrochemical methods. TRH immunoreactivity (IR-TRH) was present in all regions of lungfish brain examined. The telencephalon contained the highest concentrations of TRH, the diencephalon also contained a high concentration of TRH, and the medulla contained a markedly lower concentration. Similar concentration gradients (telencephalon greater than diencephalon greater than medulla) were observed for norepinephrine, dopamine, and serotonin. The identity of IR-TRH as authentic TRH was confirmed by elution profiles on HPLC. The results of this investigation demonstrated that TRH and the monoamine neurotransmitters are present in high concentrations in various regions of lungfish brain. The lungfish may represent a promising model for further studies of the interactions of TRH with these neurotransmitter systems.

Animals↗
PubMed1992

Immunoreactive vasotocin in the zebra finch brain (Taeniopygia guttata).

UNLABELLED: The distribution of vasotocin (VT)-immunoreactive cells and fibers in the zebra finch brain was studied with immunocytochemical techniques. A large number of VT-immunoreactive cells was found in the nucleus preopticus anterior and nucleus paraventricularis. In the lateral parts of the hypothalamus diffusely organized VT-immunoreactive cells were present. Some of these cells were found close to and embedded in the optic tract. An extra-hypothalamic parvocellular cell group was found at the level of the anterior commissure in the dorsal diencephalon. VT-immunoreactive fibers and varicosities were present in a number of extrahypothalamic regions i.e. the septum, the area ventralis of Tsai, the lateral habenula, the optic tectum, the substantia grisea centralis, the nucleus tractus solitarii, the lateral medulla, the nucleus intercollicularis and in the archistriatum surrounding the nucleus robustus archistriatalis. The VT-immunostaining in the lateral septum and dorsal diencephalon showed no sex differences and can not be influenced by testosterone administration. IN CONCLUSION: the topography of the central VT-immunoreactive network is similar to that in another song bird i.e. the canary; but seasonal and testosterone-dependent changes in VT-immunostaining in the lateral septum and dorsal diencephalon are only observed in the canary.

Animals↗
PubMed1996

Development of the mesencephalic and diencephalic catecholamine systems in human fetuses: uptake and release of catecholamines in vitro.

Development of catecholamine (CA) systems of the ventral mesencephalon and diencephalon were studied in human fetuses at age 6, 8, 10 and 12 weeks, evaluating the CA specific uptake and K(+)-stimulated release with the isotopic biochemical technique. In the mesencephalon, the [3H]dopamine (DA) uptake was detected as early as 6 weeks, suggesting the existence of either CA neurons or fibers. This was followed by gradual increase of the [3H]DA uptake up to 10 weeks and a subsequent fall at 12 weeks. In the diencephalon, the uptake was first observed at 8 weeks, followed by its decrease at 10 weeks and subsequent increase at 12 weeks. The dynamic uptake is considered as a manifestation of the continuous differentiation of CA neurons and sprouting of CA fibers. In contrast to uptake, no CA release was detected in response to membrane depolarization in the diencephalon and mesencephalon at any age studied, suggesting a timing dissociation between the onset of the CA uptake and K(+)-provoked release in the course of neuron differentiation in human fetuses.

Brain↗