Expression of corticosteroid-binding protein in the human hypothalamus, co-localization with oxytocin and vasopressin.

Corticosteroid-binding globulin, a specific steroid carrier in serum with high binding affinity for glucocorticoids, is expressed in various tissues. In the present study, we describe the immunocytochemical distribution of this protein in neurons and nerve fibers in the human hypothalamus. CBG immunoreactive perikarya and fibers were observed in the paraventricular, supraoptic, and sexual dimorphic nuclei in the perifornical region, as well as in the lateral hypothalamic and medial preoptic areas, the region of the diagonal band, suprachiasmatic and ventromedial nuclei, bed nucleus of the stria terminalis and some epithelial cells from the choroid plexus and ependymal cells. Stained fibers occurred in the median eminence and infundibulum. Double immunostaining revealed a partial co-localization of corticosteroid-binding globulin with oxytocin and, to a lesser extent, with vasopressin in the paraventricular and the supraoptic nuclei. Double immunofluorescence staining showed coexistence of these substances in axonal varicosities in the median eminence. We conclude that neurons of the human hypothalamus are capable of expressing corticosteroid-binding globulin, in part co-localized with the classical neurohypophyseal hormones. The distribution of CBG immunoreactive neurons, which is widespread but limited to specific nuclei, indicates that CBG has many physiological functions that may include neuroendocrine regulation and stress response.

Hypothalamic nitric oxide synthase in affective disorder: focus on the suprachiasmatic nucleus.

Depression is frequently associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which leads to repeated episodes of hypercortisolemia. Hypothalamic paraventricular neurons are believed to trigger these processes by aberrant generation and/or release of corticotropin releasing hormone, oxytocin, vasopressin, and nitric oxide (NO). Recent findings from two independent laboratories have demonstrated that the suprachiasmatic nucleus, which in part controls the cellular activity of paraventricular neurons (PVN), is also involved in affective disorder. The aim of the present study was to elucidate by stereological analysis, whether suprachiasmatic nucleus (SCN) nitric oxide synthase and neurophysin generating neurons are affected in neuropsychiatric disorders. We show that compared to controls the number of nitric oxide synthase immunoreactive neurons is greatly reduced both in depression and in schizophrenia. In subjects with affective disorder there was a correlation between the number of NOS-expressing cells and duration of treatment with antidepressants. The number of neurophysin-expressing SCN neurons was also fewer in cases with mood disorder. It is concluded that SCN-derived NO may be a relevant pathophysiological factor in neuropsychiatric disorders.

Further immunohistochemical evidence for impaired NO signaling in the hypothalamus of depressed patients.

The cellular expression of nitric oxide synthase (NOS) was studied in neurons of the Nuc. suprachiasmaticus (SCN) of depressed patients and matched controls. The number of NOS-immunoreactive SCN neurons was significantly reduced in depression. We conclude that affective disorders are accompanied by impaired hypothalamic NO signaling.

Nitric oxide synthase-containing neurons in the human hypothalamus: reduced number of immunoreactive cells in the paraventricular nucleus of depressive patients and schizophrenics.

The neuroanatomical distribution of nitric oxide synthase-immunoreactive neurons was investigated in post mortem hypothalami of 10 patients suffering from schizophrenia, eight patients with depression and 13 matched control cases. Neuronal nitric oxide synthase containing nerve cells were detected in several hypothalamic nuclei including the medial preoptic region, the ventromedial, infundibular and suprachiasmatic nuclei and the lateral hypothalamus. The vast majority of hypothalamic nitric oxide synthase-immunoreactive neurons was found to be located in the paraventricular nucleus. Both magno and parvocellular paraventricular neurons contained the enzyme. A small subset of immunoreactive parvocellular paraventricular neurons co-expresses corticotropin-releasing hormone. The supraoptic nucleus did not contain nitric oxide synthase-immunoreactive neurons. Cell counts of paraventricular nitric oxide synthase-positive neurons in controls, schizophrenics and depressed patients revealed a statistically significant reduction of cell density in the right paraventricular nucleus of depressed patients and schizophrenics as compared to controls. The total amount of nitric oxide synthase-immunoreactive paraventricular neurons was smaller in depressive and schizophrenic patients than in normal cases. The putative pathophysiologic significance of the reduced expression of paraventricular nitric oxide synthase in depressive patients might be related to the supposed regulatory function of nitric oxide in the release of corticotropin-releasing hormone and arginine-vasopressin and/or oxytocin, which have been reported to be over-expressed in the so-called endogenous psychoses, especially in depression.

Expression of hypothalamic peptides in mice lacking neuronal nitric oxide synthase: reduced beta-END immunoreactivity in the arcuate nucleus.

The gas nitric oxide (NO) is an important messenger in brain signaling. Along with many other functions, NO is thought to influence the expression and/or release of various hypothalamic hormones (corticotropin-releasing hormone (CRH), gonadotropin-releasing hormone (GnRH) and vasopressin). To learn more about the role of NO in neuroendocrine mechanisms, we studied in mutant mice lacking neuronal isoform of NO synthase (nNOS) the cellular expression of CRH, neurophysin (the carrier protein of vasopressin/oxytocin) and pro-opiomelanocortin (POMC), as well as of the POMC-derived peptides beta-endorphin (beta-END), alpha-melanocyte-stimulating hormone (alpha-MSH) and corticotropin (ACTH) by use of immunohistochemistry and in situ hybridization. Additionally, the remaining NO-generating capacities of the nNOS minus mice were investigated by NADPH-diaphorase histochemistry and citrulline immunohistochemistry as well as by immunohistochemical localization and Western blot analysis of endothelial NOS (eNOS) and nNOS isoforms. Amongst all hypothalamic peptides under investigation, only beta-END was found to be altered in mutant mice. A morphometric analysis of beta-END producing neurons of the arcuate nucleus revealed that significantly less cells were immunoreactive in mutant mice, whereas the expression of the precursor POMC as well as of other POMC-derived peptides was found to be unchanged. In addition to that, fewer beta-END-immunoreactive fibers were found in the paraventricular nucleus of nNOS minus mice in comparison to wild-type animals. Hence, the reduction of hypothalamic beta-END is probably a posttranslational event that might reflect a disturbed endorphinergic innervation of those hypothalamic neurons which normally express nNOS.

Cathepsin L immunoreactivity in the hypothalamus of normal, streptozotocin-diabetic and vasopressin-deficient Brattleboro rats.

The immunolocalization of cathepsin L in the hypothalamus of normal rats was compared with the distribution of the enzyme in streptozotocin-treated animals and in vasopressin-deficient rats (Brattleboro strain). In rats with a normal metabolic status the neurons of magnocellular nucl. supraopticus and paraventricularis stood out by intense immunostaining for cathepsin L. In rats suffering from an experimentally induced diabetes mellitus and in homozygous Brattleboro rats we observed a strong reduction in enzyme immunoreactivity in these nuclei. Since cathepsin L is capable of splitting certain hypothalamic neuropeptides that are changed in diabetic animals, a role of the enzyme in the metabolism of these peptides is imaginable. Decrease in immunoreactive cathepsin L in vasopressin-deficient rats points to a possible involvement of the enzyme in the control of fluid homeostasis.

Cystatin C containing neurons in human postmortem hypothalamus.

The regional distribution and cellular localization of cystatin C in neurons of human postmortem hypothalamic was studied by use of peroxidase-anti-peroxidase technique. Cystatin C (earlier named gamma-trace) was found to be present in multiple nerve cells belonging to nuclei supraopticus, paraventricularis and arcuatus. We speculate that the occurrence of cystatin C in human cerebrospinal fluid is the result of a release of the protein from these neurons into the ventricular system.

Immunohistochemical analysis of thiol: protein disulfide oxidoreductase in hypothalamic neurons of Brattleboro rat.

The immunolocalization of thiol: protein disulfide oxidoreductase (TPO) in CNS of Wistar rats and homozygous Brattleboro rats was investigated by use of monospecific antiserum and Sternberger's unlabelled immunoenzyme technique. It was revealed that TPO is present in hypothalamic neurons belonging to nucleus supraopticus and paraventricularis. The number of immunopositive nerve cells was reduced in Brattleboro rats as compared to Wistar rats. It was concluded that TPO must have tasks in CNS unrelated to the management of vasopressin production and/or processing.

Distribution of cathepsin D immunoreactivity in the central nervous system of rat and selected brain regions of man.

The regional distribution and cellular localization of cathepsin D immunoreactivity was demonstrated at the light microscopic level in the CNS of rat and man by use of unlabelled immunoenzyme technique. A wide but uneven distribution was substantiated for the rat brain. Furthermore, we present evidence that antiserum produced against rat liver enzyme is capable of recognizing cathepsin D in human brain.

Proctolin-related material in the mouse brain as revealed by immunohistochemistry.

By use of a specific antiserum against the insect peptide proctolin we were able to identify proctolin-immunoreactive neurons in the mouse brain. These nerve cells belong to the nuc. mesencephalicus n. trigemini. Furthermore, the antiserum stained very few nerve fibers with varicosities in the immediate neighborhood of the roof of the third ventricle. The chemical identity of the immunoreactive material with genuine proctolin remains to be elucidated.

Cerebral insulin-like immunoreactivity in rats and mice. Drastic decline during postnatal ontogenesis.

We studied the behavior of the insulin-like immunoreactivity in brains of rats and mice during the first 20 d post natum by immunohistochemistry and radioimmunoassay. It was found that a dramatic decline in the concentration of the peptide, accompanied by a strong reduction of immunoreactive cells, takes place during this period. A possible role of cerebral insulin as a promoter of nerve cell growth and development is briefly discussed.

Insulin-like immunoreactivity in the human brain- A preliminary report.

The localization and regional distribution of insulin-like immunoreactivity (IRI) was studied in human brain autopsy material using the indirect immunofluorescence technique. A positive reaction for IRI could be observed in many neurons of the hypothalamus, the hippocampus, corpus amygdaloideum, medulla oblongata (especially within the nuclei of cranial nerves IX, X and XII), and the cerebral cortex, whereas the cerebellar cortex was lacking in immunohistochemically detectable insulin-like material. No nerve fibres containing polypeptides could be revealed. Additionally, the insulin content of various brain regions was estimated by radioimmunoassay. Insulin concentrations in human nervous tissue were found to be elevated in comparison to blood plasma levels.

Immunoreactive glucagon in neurons of various parts of the human brain. Demonstration by immunofluorescence technique.

The presence of glucagon-like immunoreactivity in nerve cells of different parts of the human brain was demonstrated by the indirect immunofluorescence technique. A bright fluorescent reaction was observed in the pyramidal cells of lamina V of the Neocortex. Less prominent concentrations of the glucagon-like material were detected in a few pyramidal cells of the Hippo-campus and in some neurons of the Presubiculum and Subiculum. Within the Corpus amygdaloideum, only a few magnocellular neurons showed a positive reaction. The Hypothalamus was evidenced by a moderate, but widely distributed, reaction in magnocellular and medium-sized nerve cells in different nuclei (especially Nuc. ventromedialis and Nuc. arcuatus). A strong immunofluorescence was localized to some neurocytes in the Nuc. amibigus, and Nuc. n. hypoglassi. The Purkinje cells of the cerebellar cortex were free from immunoreactive material, but fluorescence occurred in some very small nerve cells of the Cerebellum (probably granular cells). A dependence of the strength of immunofluorescence of the time delay between autopsy and death is shown.

Are certain peculiarities in the distribution of somatostatin-like immunoreactivity (SLI) in the brain of sand rats (Psammomys obesus) possibly connected with an altered carbohydrate metabolism?

The hypothalamic and extrahypothalamic distribution of somatostatin-like immunoreactivity (SLI) was investigated in fed adult sand rats (Psammomys obesus) of both sexes using the immunofluorescence technique. Blood glucose and insulin concentrations were determined in these animals prior to decapitation. In a blind study, the amount of immunofluorescence of certain CNS areas and the glucose: Insulin ratio were compared and found to be connected: High amounts of SLI were detected in the dorsal hippocampus, in some hypothalamic nuclei and the median eminence of rats displaying low glucose levels. Sand rats with high blood glucose values did not show SLI in the hippocampal formation and the immunofluorescence of the circumventricular (hypothalamic) regions and the Eminentia mediana was drastically reduced. A possible correlation of SLI with insulin concentrations in the blood could not be revealed. The data obtained are discussed as a possible expression of a CNS influence on glucoregulation in this species.

Regional distribution of glucagon-like immunoreactive material in the brain of rats and sand rats. An immunohistochemical investigation.

Glucagon-like immunoreactivity was demonstrated in different parts of rat and sand rat central nervous system by the indirect immunofluorescence method. In hyperglycemic animals the level of immunoreactive material was reduced to a great extent.

An immunofluorescent reaction appears to insulin-antiserum in different CNS regions of two rat species.

Using immunofluorescence technique a positive reaction to insulin antiserum could be revealed in different parts of the CNS of Wistar rats and sand rats.