The glucocorticoid receptor in the adrenal gland is localized in the cytoplasm of adrenaline cells.
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Adrenal Glands↗
Biomedical subjects
S Ceccatelli
Publications and source records attributed to S Ceccatelli.
Distribution and coexistence of corticotropin-releasing factor-, neurotensin-, enkephalin-, cholecystokinin-, galanin- and vasoactive intestinal polypeptide/peptide histidine isoleucine-like peptides in the parvocellular part of the paraventricular nucleus.
The distribution of several peptides, corticotropin-releasing factor (CRF), neurotensin (NT), enkephalin (ENK), vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), cholecystokinin (CCK), thyrotropin-releasing hormone (TRH) and galanin (GAL) was studied in detail with immunohistochemistry in the various subdivisions of the parvocellular part of the rat hypothalamic paraventricular nucleus (PVN). Using a double-staining method and elution-restaining technique, the coexistence of CRF- and NT-like immunoreactivities (LI) with other neuropeptides was analyzed. Our results indicate that coexistence of two or more peptides in the PVN is common, and revealed that about 30% of the CRF neurons contain NT-LI and about 20% ENK-LI, whereas other peptides only occur in small fractions of the CRF cells. Thus, it seems possible to define three major subpopulations of CRF neurons, one containing NT-LI, another one containing ENK-LI and a third one apparently lacking these peptides. Conversely, about 60% of both NT- and ENK-immunoreactive neurons lacked CRF-LI. A large proportion of the small population of VIP/PHI neurons contained NT-LI. TRH neurons represented a neuron population completely distinct from the CRF neurons. Also, it did not seem to contain any of the other peptides studied with the rare exception of ENK-LI. Neuropeptides present in the PVN and presumably in nerve fibers of the external layer of the median eminence may participate in the control of the anterior pituitary hormone secretion. Whereas the role of CRF and TRH is well established, the physiological role of the other peptides studied here is still unclear.
Animals↗
Hypothalamic neurosecretory systems and their messenger molecules.
The distribution and cellular localization of several transmitters, transmitter synthesizing enzymes and peptides in the arcuate, paraventricular and supraoptic nuclei are described with special focus on coexistence of messenger molecules. The role of these compounds in various neuroendocrine events is discussed.
Animals↗
A subpopulation of dopaminergic neurons in rat ventral mesencephalon contains both neurotensin and cholecystokinin.
The coexistence of the neuropeptides neurotensin and cholecystokinin and the catecholamine-synthesizing enzyme tyrosine hydroxylase within neurons of the ventral mesencephalon was analyzed using an immunofluorescence triple-labeling technique. Virtually all of the neurotensin-positive cell bodies in the ventral tegmental area, medial substantia nigra pars compacta, retrorubral field, and rostral and caudal linear raphe nuclei were found to contain both cholecystokinin and tyrosine hydroxylase immunoreactivities. The degree of colocalization was lower and more variable in other regions including the ventral and central periaqueductal grey matter and dorsal raphe nucleus. It appeared that immunoreactivities for these 3 neuroactive substances were not contained within the same axonal-like fibers and terminals in the ventral midbrain. These results demonstrate that a subpopulation of dopaminergic neurons, which presumably comprise part of the ascending mesotelencephalic system, contains the two peptides neurotensin and cholecystokinin. Thus, the data suggest a morphological basis for some of the reported functional interactions of these 3 putative neurotransmitters/neuromodulators within this system.
Animals↗
Some blood vessels in the rat median eminence are surrounded by a dense plexus of vasoactive intestinal polypeptide/peptide histidine isoleucine (VIP/PHI) immunoreactive nerves.
Using immunohistochemistry at the light and electron microscopic level some blood vessels along the median eminence were shown to be surrounded by dense networks of vasoactive intestinal polypeptide/peptide histidine isoleucine (VIP/PHI)-positive fibers. VIP and PHI released from these fibers may contribute to the elevated levels of these two peptides measured in portal blood as compared to peripheral blood by radioimmunoassay. VIP and PHI may also be important in the control of blood flow through the median eminence.
Animals↗
Coexistence of peptides with classical neurotransmitters.
In the present article the fact is emphasized that neuropeptides often are located in the same neurons as classical transmitters such as acetylcholine, 5-hydroxy-tryptamine, catecholamines, gamma-aminobutyric acid (GABA) etc. This raises the possibility that neurons produce, store and release more than one messenger molecule. The exact functional role of such coexisting peptides is often difficult to evaluate, especially in the central nervous system. In the periphery some studies indicate apparently meaningful interactions of different types with the classical transmitter, but other types of actions including trophic effects have been observed. More recently it has been shown that some neurons contain more than one classical transmitter, e.g. 5-HT plus GABA, further underlining the view that transfer of information across synapses may be more complex than perhaps hitherto assumed.
Animals↗
Immunohistochemical evidence for a spinothalamic pathway co-containing cholecystokinin- and galanin-like immunoreactivities in the rat.
Using indirect immunofluorescence technique combined with retrograde tracing as well as surgical lesions, a system of spinothalamic neurons containing both galanin- and cholecystokinin-like immunoreactivity has been defined. The cell bodies are located in the lumbar segments L1-L5 with a preferential localization dorsal to the central canal at rostral levels and lateral to the canal at caudal levels. The cells project via the ventral part of the lateral funiculus to the most ventral and posterior parts of thalamus. Here a distinct, varicose terminal network was seen extending caudally from an area lateral to the medial lemniscus, running medially over the medial lemniscus, traversing the parafascicular nucleus and running dorsal to the fasciculus retroflexus into the periventricular gray matter. Transection of various parts of the spinal cord as well as retrograde tracing experiments indicate that the spinothalamic galanin cholecystokinin system represents a crossed pathway. The present results demonstrate that a spinothalamic system can be characterized by its content of galanin- and cholecystokinin-like peptides, two putative messenger molecules. It is only a minor component of the total spinothalamic projection.
Animals↗
Analysis of peptide histidine-isoleucine/vasoactive intestinal polypeptide-immunoreactive neurons in the central nervous system with special reference to their relation to corticotropin releasing factor- and enkephalin-like immunoreactivities in the paraventricular hypothalamic nucleus.
The distribution of peptide histidine-isoleucine (PHI) and vasoactive intestinal polypeptide (VIP), two peptides derived from the same precursor molecule, was analysed with immunohistochemistry in the central nervous system of the rat, and to a limited extent in some other species including sheep, monkey and man. Special attention was focused on possible cross-reactivity between PHI antisera and corticotropin releasing factor in parvocellular neurons in the hypothalamic paraventricular nucleus projecting to the external layer of the median eminence. (1) Characterization of the PHI and VIP antisera revealed that they recognized different sequences of the peptide molecules. One of the PHI antisera (PHI-N), although mainly N-terminally directed, also probably contained an antibody population directed against the C-terminal amino acid in PHI which is an amidated isoleucine. Rat and human corticotropin releasing factor but not ovine also have an amidated isoleucine in C-terminal position. (2) PHI- and VIP-like immunoreactivity were found with parallel and overlapping distribution in all areas investigated in the rat central nervous system. In many cases coexistence of the two immunoreactivities could be directly demonstrated. PHI neurons were found in some areas so far not know to contain PHI/VIP neurons, including the dorsal septum, the septofimbrial nucleus, the stria terminalis and lamina V of the spinal cord. (3) Using an antiserum directed against the amino acid sequence 111-122 of the VIP/PHI precursor, immunoreactive cell bodies were seen in some areas containing VIP and PHI neurons. PHI- and VIP-like immunoreactivity were expressed in parallel in increasing amounts in the superficial laminae of the dorsal horn after transection of the sciatic nerve [G. P. McGregor et al. (1984) Neuroscience 13, 207-216; S. A. S. Shehab and M. E. Atkinson (1984) J. Anat. 139, 725; S. A. S. Shehab and M. E. Atkinson (1986) Expl Brain Res. 62, 422-430]. (5) The PHI-N antiserum stains large numbers of immunoreactive cells in the parvocellular part of the paraventricular nucleus and these cells are mostly identical with corticotropin releasing factor-positive neurons. Absorption experiments suggested that this PHI-N-like immunoreactivity to a large extent represented cross-reactivity with rat CRF and that earlier demonstration of many PHI-positive neurons in the paraventricular nucleus probably represents an artefact as proposed by F. Berkenbosch et al. (Neuroendocrinology 44, 338-346). However, some cells did, in fact, contain VIP- as well as PHI-like immunoreactivity as was shown with antisera not cross-reacting with corticotropin releasing factor.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Immunohistochemical evidence for a magnocellular somatostatin cell group in the anterior paraventricular thalamus of the rat.
By use of the indirect immunofluorescence technique a small group of large somatostatin-positive neurons is described in the subependymal area of the anterior paraventricular thalamus of the male rat. Retrograde-tracing experiments suggest that they project to areas outside the blood-brain barrier.
Animals↗
Immunohistochemical analysis of the effects of cysteamine on somatostatin-like immunoreactivity in the rat central nervous system.
The brain and spinal cord of untreated and cysteamine-treated rats were analyzed with immunohistochemistry using antisera raised against somatostatin (SOM)-28(1-14) and SOM-28(15-28). Sections incubated with increasing dilutions of antiserum were evaluated subjectively on coded slides and with computer-assisted image analysis. For control experiments, antisera raised against methionine-enkephalin, neuropeptide Y (NPY) and dynorphin (DYN)(1-13) were used. The latter antiserum does not visualize the conventional DYN systems in the brain, but reacts with an unknown epitope, which here could be shown to be present in SOM neurons. In cysteamine-treated rats a marked decrease in SOM-28(15-28)-like immunoreactivity (1.1) could be recorded subjectively at all antibody concentrations in fibers in several brain areas, including nucleus accumbens, tuberculum olfactorium and the hypothalamic ventromedial and arcuate nuclei. In these areas SOM-LI is fairly weak in untreated rats. In SOM-rich regions such as the median eminence and the dorsal horn of the spinal cord, the depleting effect of cysteamine could be recorded subjectively only when diluted antisera were used. Image analysis confirmed the subjective analysis, and, in addition, differences between controls and cysteamine-treated rats could be shown also at high antiserum concentrations. SOM-28(15-28)-immunoreactive cell bodies could be seen in the brains of either control or drug-treated rats. No effect of cysteamine could be observed when antiserum raised to SOM-28(1-14) was used. Cysteamine did not seem to affect enkephalin-LI, NPY-LI or an epitope in SOM neurons reacting with DYN(1-13) antiserum. After preabsorption of SOM-28(15-28) antiserum with SOM-28(15-28) peptide, the staining patterns described above disappeared completely. However, if the SOM-28(15-28) peptide was pretreated with a high concentration (1 M) of cysteamine before being used for absorption with SOM antiserum, no blocking effect could be observed. The present results demonstrate with immunohistochemistry that cysteamine causes depletion of SOM-28(15-28) in fibers but apparently not in cell bodies. No effects on SOM-28(1-14)-LI were observed. This supports earlier evidence that cysteamine interacts with the disulphide bond in the SOM-28(15-28) molecule. The present results also emphasize that when analyzing drug effects on peptide neurons with immunohistochemical techniques, it is important to use dilution series of antibodies and preferably to carry out the analysis with objective image analysis methods.
Animals↗
Role of mitochondria in neuronal apoptosis.
Apoptosis is a controlled form of cell death that participates in the demise of neuronal cells during development, neurodegenerative disorders and exposure to neurotoxic agents. In recent years, the mitochondria have emerged as being pivotal in controlling apoptosis. They house a number of apoptogenic molecules that are released into the cytoplasm at the onset of apoptosis. These include cytochrome c, apoptosis-inducing factor and various caspases. Mitochondria also play an important role in intracellular Ca(2+) regulation, which is crucial to excitotoxic neurodegeneration. Alterations in energy (ATP) production by mitochondria (due to hypoxia or mutations in genes encoding mitochondrial proteins of the electron transport chain) can induce apoptosis in neurons or increase their sensitivity to apoptosis.
Adenosine Triphosphate↗
In situ hybridization studies on mRNAs for cholecystokinin, calcitonin gene-related peptide and choline acetyltransferase in the lower brain stem, spinal cord and dorsal root ganglia of rat and guinea pig with special reference to motoneurons.
In situ hybridization techniques were used to analyse the distribution of cholecystokinin (CCK) mRNA in the lower brain stem, spinal cord and dorsal root ganglia of the rat and guinea pig, in comparison with that of mRNAs for calcitonin gene-related peptide (CGRP) and choline acetyltransferase. In the rat, CCK mRNA was found in numerous motoneurons in the spinal cord as well as in the motor trigeminal, facial and hypoglossal nuclei. Coexistence of CCK mRNA and CGRP mRNA could be established in spinal and brain stem motoneurons. Conversely, in the guinea pig CCK mRNA could only be detected in few motoneurons in the spinal cord. In both species, CCK mRNA was present in the spinal trigeminal nucleus and in the dorsal horn of the spinal cord, in numerous small cells located in the outer laminae (mainly II-IV), and in the rat was also found in large cells in laminae IV and V. Few small cells in laminae VI-VIII and X of the spinal cord and cells in several brain stem nuclei, such as the solitary tract, gracile and cuneate nuclei, also showed CCK mRNA in the rat. In the guinea pig brain stem CCK mRNA was found, among others, in the solitary tract nucleus, pontine reticular formation and pontine periventricular grey. In dorsal root ganglia CCK mRNA was abundant in the guinea pig, but almost absent in the rat, where only single cells were found that expressed low levels of this mRNA.
Animals↗
Coexistence of TRH with other neuroactive substances in the rat central nervous system.
Colocalization of thyrotropin-releasing hormone-like immunoreactivity with other neuroactive substances was examined immunohistochemically in colchicine-treated rat brains using double-staining or elution-restaining methods. Thyrotropin-releasing hormone-like immunoreactivity was shown to be located in the same neurons as: 1. enkephalin-, gamma-amino butyric acid- and tyrosine hydroxylase-, but not somatostatin-like immunoreactivity in the glomerular layer of the olfactory bulb 2. oxytocin- and cholecystokinin-, but not vasopressin-like immunoreactivity in the supraoptic nucleus 3. cholecystokinin-like immunoreactivity in posterior pituitary 4. enkephalin-like immunoreactivity in the perifornical area of the hypothalamus and 5. neuropeptide Y- and neurotensin-like immunoreactivity in the periaqueductal central grey. These findings provide further examples of coexistence of thyrotropin-releasing hormone with classical neurotransmitters and/or peptides in the rat central nervous system.
Animals↗