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At least 235 records · Page 13Linked to original sources
PubMed1971

The effect on drinking of peptide precursors and of shorter chain peptide fragments of angiotensin II injected into the rat's diencephalon.

1. Recently it has been shown that injection of angiotensin II into the anterior diencephalon causes the rat to drink water. In the present experiments the dipsogenic action of a number of other substances including substances related to angiotensin was tested.2. Injection of 0.001 Goldblatt u. renin into the angiotensin-sensitive region causes the water-replete rat to drink. Drinking is slower in onset and continues for longer than after injection of angiotensin II.3. Synthetic tetradecapeptide renin substrate and angiotensin I were as effective as angiotensin II at causing water-replete rats to drink.4. beta-aspartic acid(1)-valine(5)-angiotensin II was also fully effective; but the D-arginine substituted octapeptide was much less effective.5. The (2-8) heptapeptide retained about 50% of the dipsogenic activity of the octapeptide, whereas the absence of phenylalanine at the other end of the peptide chain in the (1-7) heptapeptide results in an inactive compound.6. The (3-8) hexapeptide and the (4-8) pentapeptide, both of which have phenylalanine at the end of the chain, and the (1-4) and (5-8) tetrapeptide fragments of angiotensin II showed only a slight action on intake of water.7. Kallikrein, bradykinin, adenosine-3'5-cyclic phosphate, vasopressin and oxytocin caused no drinking when injected into the angiotensin-sensitive region.8. It is concluded that the requirements for the dipsogenic activity of angiotensin are the same as those for its other biological actions with the qualification that the precursor peptides are also active, presumably because they give rise to angiotensin II locally.

Angiotensin II↗
PubMed1977

Immunoreactive luteinizing hormone releasing factor (LRF) in pituitary stalk plasma from female rats: effects of stimulating diencephalon, hippocampus and amygdala.

1. Previous studies on the effect of preoptic and median eminence stimulation on the immunoreactive LRF content of pituitary stalk blood from pro-oestrous rats have been extended. Stimulation of the suprachiasmatic nuclei and anterior hypothalamic area produced increments in LRF which were 66 and 18% respectively, of that produced by preoptic stimulation, and 38 and 9%, respectively, of that produced by stimulation of the median emience. Stimulation of the amygdala and hippocampus had no effect. 2. The LRF response was not affected significantly when preoptic stimulation was accompanied by stimulation of the hippocampus. 3. In animals subjected to section of the dorsal afferents of the diencephalon, the LRF response to preoptic stimulation was similar to that in intact rats. However, the facilitatory effect of oestrogen on the LRF response to preoptic stimulation was significantly reduced in the roof sectioned compared with intact animals. The post-operative resumption of oestrous cycles was delayed but not abolished by dorsal deafferentation.

Amygdala↗
PubMed1989

In vitro localization of thermosensitive neurons in the rat diencephalon.

Many thermosensitive neurons in the preoptic area-anterior hypothalamus (POAH) are believed to function in thermoregulation. Although many other diencephalic regions are implicated in thermoregulation, measurements of single-cell activity during localized thermal stimulation in these regions are lacking. Utilizing horizontal tissue slices, we have recorded single-unit activity throughout the rat diencephalon in response to localized thermal stimulation. Thermosensitive cells were identified in 18 nuclei. The proportions of each subpopulation inside vs. outside the POAH were similar: POAH (n = 83 cells); warm = 31%, cold = 4%, warm-cold = 1%, and temperature insensitive = 64%, outside POAH (n = 198 cells; warm = 39%, cold = 6%, warm-cold = 4%, and temperature insensitive = 51%. However, nuclei located rostral and lateral to POAH contained a large percentage of warm-sensitive cells (49-63%). Caudal nuclei contained approximately half of the cold-sensitive cells studied. This wide distribution of thermo-sensitive cells suggests that many diencephalic areas, besides the POAH, are capable of thermoreception and thermointegration. Moreover, many of these thermosensitive cells may function in other systems (e.g., reproduction, feeding, and water balance) which central and environmental temperatures are known to influence.

Animals↗
PubMed1991

Ontogeny of somatostatin gene expression in rat diencephalon.

Somatostatin gene expression is first detectable, using in situ hybridization, on the 14th fetal day in rat diencephalon. Other structures expressing somatostatin messenger RNA include the anterior basal periventricular nucleus, amygdalo-hippocampal complex, dorsolateral thalamus and distinct areas in the parieto-frontal cortex. Semiquantitative analysis reveals that somatostatin synthesis increases progressively throughout the last third of fetal life and onto postnatal life.

Animals↗
PubMed1994

An immunohistochemical study of the telencephalon and the diencephalon in a Myxinoid jawless fish, the Pacific hagfish, Eptatretus stouti.

The forebrain of adult hagfishes (jawless craniates, Myxinoidea) displays a unique morphology. The forebrain is thick-walled and well-differentiated cytoarchitecturally but lacks a well-developed ventricular system, and there is a pronounced compression of the entire brain along the longitudinal axis. This combination of characters obscures the boundaries between the major subdivisions of the forebrain; thus, some elementary morphological issues, such as the location of the pallial-subpallial and the telencephalic-diencephalic boundaries, have remained a matter of dispute over the past 100 years. In an attempt to resolve some of these issues, we investigated the chemoarchitecture of the forebrain of the Pacific hagfish, Eptatretus stouti. Because a number of previous studies of other craniates, mainly gnathostomes, have shown that the spatial distribution of some neuroactive substances and enzymes mirrors the main subdivisions of the forebrain, we localized acetylcholinesterase, enkephalins, substance P, tyrosine hydroxylase, and alpha-melanocyte stimulating hormone by means of histochemistry. Surprisingly, our data show that there are very limited chemoarchitectural similarities shared by hagfishes and other craniates. Some striking similarities occur in the organization of the catecholaminergic systems. Hagfishes, as well as other craniates, possess catecholaminergic cell groups at the ventral junction of the mesencephalon and diencephalon that give rise to a catecholaminergic innervation of the basal forebrain. The distribution of all other substances examined is dissimilar to that found in other craniates. In particular, there are many neurons positive for acetylcholinesterase in the pallium; the subpallium contains relatively small amounts of neuroactive peptides; and the highest densities of structures positive for neuroactive peptides and acetylcholinesterase occur in the central prosencephalic nucleus. Therefore, a comparative chemoarchitectural analysis proved to be of limited value in revealing homologies among cell groups of hagfishes, lampreys, and gnathostomes. We conclude that some chemoarchitectural features that appear to be well conserved within gnathostomes, such as the histochemical differences between the pallium and subpallium, may result from evolutionary change early in craniate history.

Acetylcholinesterase↗
PubMed1979

Brain stem, cerebellum and diencephalon of the marmoset (Callithrix jacchus).

The gross anatomy and the internal structure of the marmoset (Callithrix jacchus) brain stem, cerebellum and diencephalon are described based on the observations made on the material obtained from 10 adult animals (native name: sagui). 5 brains were used for gross anatomical observations; the other 5 brains, included in toto in celloidin, were cut into serial sections, properly stained and used for comparative studies of the internal structure. Only general descriptions are given considering this part of the encephalon because, in further papers, it is intended to go on describing in details the nervous system of this small primate, very common in Brazilian jungles and easily domesticated. It shows to be a very good and inexpensive animal for neurophysiological experiments.

Animals↗
PubMed1979

The cell masses in the diencephalon of Amphisbaena darwini heterozonata Burmeister (Amphisbaenia, Squamata, Reptilia).

The cell masses of the diencephalon of Amphisbaena darwini heterozonata are studied and confronted with those of other reptiles, specially with the burrowing ophidian Typhlopidae. The main differences are in the thalamus dorsalis. The amphisbaenids share with the Typhlopidae the absence of the lateral and pretectal geniculate bodies, and share with the squamate reptiles, differing from the typhlopids, the remaining structures of the dorsal thalamus, characterized by the well-developed nucleus rotundus. These features support the idea that the amphisbaenids could be situated within the Squamata at the same level as in Ophidia and Lacertilia. The adaptive processes toward a burrowing behavior have not been the same in amphisbaenids and in the typhlopids. The causes of the dissimilarities of the dorsal thalamus could be related to other sense and non-sense systems apart from the optic. The morphology of the elements of the cell masses has been studied by the Golgi method.

Animals↗
PubMed1992

Distribution of oxytocin and vasopressin neurons in the diencephalon of the Japanese horseshoe bat, Rhinolophus ferrumequinum. An immunohistochemical study.

The distribution of oxytocin (OXT) and vasopressin (VP) neurons in the diencephalon of the hibernating Japanese horseshoe bat, Rhinolophus ferrumequinum, was immunohistochemically investigated by the avidin-biotin complex method. Magnocellular OXT and VP neurons were localized mainly in the paraventricular nucleus and the supraoptic nucleus. In addition to these main nuclei, both kinds of magnocellular neurons were also found in the periventricular nucleus, perifornical area and lateral hypothalamic area. Extensively distributed parvocellular neurons containing only VP were observed in the rostral and middle portions of the suprachiasmatic nucleus. The size of OXT and VP magnocellular neurons was almost equal in the paraventricular and ventromedial supraoptic nuclei, whereas VP neurons were significantly larger than OXT neurons in the dorsolateral supraoptic nucleus. The OXT and VP cells in the ventral supraoptic nucleus showed a distinctive elliptical shape. Both OXT and VP fibers were distributed in the lateral habenular nucleus, stria medullaris thalami, lateral preoptic area, stria terminalis, and medial and supracapsular part of the bed nucleus of the stria terminalis. Moreover, OXT fibers were found in the substantia nigra, and VP fibers were noted in the nucleus reunions and the paraventricular nucleus of the thalamus.

Animals↗
PubMed1985

Mapping of glucocorticoid receptor immunoreactive neurons in the rat tel- and diencephalon using a monoclonal antibody against rat liver glucocorticoid receptor.

By means of a monoclonal antibody against the rat liver glucocorticoid receptor (GR) in combination with the indirect immunoperoxidase technique it has been possible to demonstrate GR-immunoreactive nerve and glial cell nuclei all over the tel- and diencephalon of the male rat. Strongly GR-immunoreactive nerve cell nuclei were only present in the parvocellular part of the paraventricular hypothalamic nucleus, in the anterior periventricular hypothalamic nucleus, in the ventral part of the mediobasal hypothalamus, and in the CA1 and CA2 subregion of the hippocampal formation. Within the paraventricular hypothalamic nucleus a substantial overlap exists between the GR-immunoreactive area and the CRF-immunoreactive area. Medium to high densities of moderately GR-immunoreactive nerve cell nuclei were present all over the cortical hemispheres. Medium densities of moderately GR-immunoreactive nerve cells were demonstrated in many thalamic nuclei and in the central amygdaloid nucleus. After adrenalectomy the GR immunoreactivity was predominantly located in the pericaryon. Upon acute corticosterone treatment of adrenalectomized male rats, the GR immunoreactivity was again mainly demonstrated in the nerve cell nuclei indicating that corticosterone can translocate GR from the cytoplasm to the cell nuclei. It is suggested that the hypothalamic GR may be involved in the regulation of especially CRF secretion but also in the secretion of other anterior pituitary hormones such as TRH and somatostatin.

Adrenalectomy↗
PubMed2002

Close juxtapositions between luteinizing hormone-releasing hormone-immunoreactive neurons and corticotropin-releasing factor-immunoreactive axons in the human diencephalon.

Gonadal functions are modulated by corticotropin-releasing factor (CRF) in the rat via direct suppression of LH-releasing hormone (LHRH) release. Although there is evidence of direct morphological contacts between the LHRH and CRF-immunoreactive (-IR) structures in the rat hypothalamus, little is known about the morphological base of CRF-influenced LHRH release in man. Thus, we studied the distribution of the CRF-IR and LHRH-IR systems in the human diencephalon and revealed putative CRF-LHRH juxtapositions using double label immunohistochemistry. LHRH-IR cells were present mainly in the infundibular region and the medial preoptic area. CRF-IR neuronal structures were observed in the periventricular area, paraventricular nucleus, infundibular region, and median eminence. CRF-LHRH juxtapositions were found mainly in the infundibulum and median eminence. Few juxtapositions were detected in the medial preoptic area. In these regions, black diaminobenzidine/silver-labeled CRF-IR fibers abutted fusiform brown diaminobenzidine-labeled LHRH neurons, usually forming multiple contacts. Examination of semithin sections of these close associations with the aid of oil immersion revealed no cleft between CRF-IR nerve terminals contacting LHRH-IR structures. These findings suggest that the juxtapositions between the LHRH-IR and CRF-IR neurons may be functional synapses forming the morphological substrate of the CRF-controlled LHRH secretion. Moreover, the wide distribution of CRF-IR elements suggests that CRF controls other diencephalic functions as well.

Adult↗
PubMed1997

MR imaging of progressive downward herniation of the diencephalon.

Some clinicians have challenged the clinicopathologic correlation in patients with brain herniation from acute mass lesions. Earlier studies have questioned the significance of downward displacement of the brainstem in supratentorial herniation. Using recent generation MRI, we studied a patient with an acute hemorrhagic infarction. MRI demonstrated significant compression of the diencephalon with downward displacement of the midbrain and hyperintensity on T2-weighted sequences in the lateral mesencephalon during progression from early diencephalic stage to midbrain upper pons stage of herniation. This is the first intra vitam documentation of diencephalic herniation by MR imaging and confirms rostrocaudal deterioration usually found at autopsy.

Aged↗
PubMed2005

Shh-dependent formation of the ZLI is opposed by signals from the dorsal diencephalon.

The zona limitans intrathalamica (ZLI) is located at the border between the prospective ventral thalamus and dorsal thalamus, and functions as a diencephalic signaling center. Little is known about the mechanism controlling ZLI formation. Using a combination of fate-mapping studies and in vitro assays, I show that the differentiation of the ZLI from progenitor cells in the alar plate is initiated by a Shh-dependent signal from the basal plate. The subsequent dorsal progression of ZLI differentiation requires ongoing Shh signaling, and is constrained by inhibitory factors derived from the dorsal diencephalon. These studies demonstrate that self-organizing signals from the basal plate regulate the formation of a potential patterning center in the ZLI in an orthogonal orientation in the alar plate, and thus create the potential for coordinated thalamic patterning in two dimensions.

Animals↗
PubMed2006

Hedgehog signalling from the zona limitans intrathalamica orchestrates patterning of the zebrafish diencephalon.

Midway between the anterior neural border and the midbrain-hindbrain boundary, two well-known local signalling centres in the early developing brain, is a further transverse boundary with putative signalling properties -- the zona limitans intrathalamica (ZLI). Here, we describe formation of the ZLI in zebrafish in relation to expression of sonic hedgehog (shh) and tiggy-winkle hedgehog (twhh), and to development of the forebrain regions that flank the ZLI: the prethalamus and thalamus. We find that enhanced Hh signalling increases the size of prethalamic and thalamic gene expression domains, whereas lack of Hh signalling leads to absence of these domains. In addition, we show that shh and twhh display both unique and redundant functions during diencephalic patterning. Genetic ablation of the basal plate shows that Hh expression in the ZLI alone is sufficient for diencephalic differentiation. Furthermore, acquisition of correct prethalamic and thalamic gene expression is dependent on direct Hh signalling. We conclude that proper maturation of the diencephalon requires ZLI-derived Hh signalling.

Animals↗
PubMed1985

Effects of idebenone (CV-2619) on endogenous monoamine release and cyclic AMP formation in diencephalon slices from rats.

The addition of CV-2619 (10(-4) M) stimulated the release of endogenous 5-hydroxytryptamine (5-HT) markedly and that of norepinephrine (NE) slightly from slices of rat diencephalon, but it did not affect dopamine (DA) release. The addition of CV-2619 (10(-5)-10(-4) M) or 5-HT (10(-6)-10(-4) M) stimulated cyclic AMP formation in a concentration-dependent manner. Methysergide (10(-4) M), a 5-HT receptor blocker, almost completely blocked CV-2619 (10(-4) M)- and 5-HT (10(-4) M)-induced cyclic AMP formation. These results suggest that CV-2619 stimulates cyclic AMP formation via endogenous monoamine, particularly, 5-HT release.

Animals↗
PubMed1981

Effect of gonadectomy on the concentrations of catecholamines in discrete areas of the diencephalon of the domestic fowl.

Concentrations of dopamine, noradrenaline and adrenaline in discrete areas of the diencephalon in male and female domestic fowl were correlated with changes in the plasma concentrations of LH induced by gonadectomy. Gonadectomized birds of both sexes exhibited raised plasma concentrations of LH and in castrated cockerels the daily administration of testosterone propionate was completely effective in preventing the postcastration rise in LH. Although no significant alterations in the brain concentrations of noradrenaline or adrenaline were observed in cockerels, the concentration of dopamine in the paraventricular nucleus (PVM), dorsomedial thalamic nucleus and mediobasal hypothalamus (MBH) were significantly raised in castrated compared with sham-operated birds by 136, 182 and 52% respectively. In each case the increase was partially suppressed by testosterone replacement therapy. In pullets, ovariectomy resulted in significant increases in the concentrations of dopamine (83%) and noradrenaline (78%) in the MBH and noradrenaline (35%) and adrenaline (34%) in the PVM. These findings suggest that in the fowl at least part of the negative feedback effect of gonadal steroids on LH secretion may be mediated by catecholaminergic mechanisms at the level of the hypothalamus.

Animals↗
PubMed1994

Neuropeptide Y-immunoreactive structures in the telencephalon and diencephalon of the white sturgeon, Acipenser transmontanus, with special regard to the hypothalamo-hypophyseal system.

An immunohistochemical study using a streptavidin-biotin method demonstrated the extensive distribution of neuropeptide Y (NPY)-like immunoreactivity in the brain of the white sturgeon, Acipenser transmontanus, with the highest density in the basal telencephalon and diencephalon. Two labeled cell groups were found in the telencephalon, in mediobasal and dorsocaudal locations. Labeled fibers were considerably dense in the ventral area. The epithalamus displayed dense networks of varicose fibers in the ganglion habenulae, but only a few fibers were seen in the organon subcommissurale. In the thalamus, two groups of labeled cells were discerned in the periventricular gray matter: an anteroventral group largely composed of cerebrospinal fluid (CSF)-contacting neurons, and a dorsocaudal group consisting of non-CSF-contacting large neurons. The hypothalamus also contained a number of CSF-contacting neurons in the periventricular areas including the nucleus lobi inferioris, the nucleus lateralis tuberis and the nucleus recessus posterioris. Labeled varicose fibers were closely associated with the hypothalamo-hypophyseal complex, the organon vasculosum hypothalami, and the saccus vasculosus. Immunoreactive cells and fibers were also detected in the dorsal region of the adenohypophysis. These results suggest that NPY or a related molecule is involved in the hypothalamic neuroendocrine mechanisms of this primitive bony fish.

Animals↗
PubMedDate not supplied

[Catecholamines in the human diencephalon].

INTRODUCTION: Catecholamines are chemical compounds which play an important role as neurotransmitters in many vital functions of the organism. The paper presents a short survey of their biosynthesis, disintegration andfunctions, with respect to the neuroanatomical location of cell groups which contain these compounds. CATECHOLAMINES IN THE HUMAN HYPOTHALAMUS: Because the authors were most interested in the behavior of catecholamines in the diencephalon, particularly in the hypothalamus, they focussed their attention on cells secreting catecholamines (dopamine, noradrenaline, adrenaline, octopamine). The paper also deals with the connections between cellular structures which emit and receive the neuronal impulses that transport catecholamines as neurotransmitters. These include the following dopaminergic systems: nigrostriatal, tuberohypophysial, retinal, periventricular, periglomerular and dopaminergic systems in mesolimbic, mesocortical and diencephalic regions. The paper also indicates other areas in human brain with adrenaline and noradrenaline secreting cells.

Catecholamines↗
PubMed1976

Histoenzymological mapping of acetylcholinesterase and butyrylcholinesterase in the diencephalon and mesencephalon of Uromastix hardwickii.

The paper deals with a detailed histochemical mapping of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in the diencephalon and mesencephalon of Uromastix hardwickii. In AChE in contrast to BChE preparations, most of the nuclei reveal intense activity Interestingly, the hypothalamic nuclei demonstrate positive reactions to AChE but totally negative reactions in BChE preparations. The enzymatic activity in fiber tracts is totally negative for AChE; on the contrary, it is intensely positive for BChE. Neurosecretory substance, in the hypothalamic region, is positive for the two preparations of the enzymes. The role of these enzymes, as related to the functional activities of the various nuclei and fiber tracts, has also been discussed.

Acetylcholinesterase↗