Biomedical subjects
Publications and source records attributed to K Seroogy.
Neuropeptides 2001, 2nd Joint Meeting of the European Neuropeptide Club and the American Summer Neuropeptide Conference (11th Annual Meeting). 6-11 May 2001 with Satellite Symposium, Israeli-French Symposium, Israel Ministry of Science, Culture and Sport, 6 May 2001, held at Maale Hachmicha and Tel Aviv University, Israel.
In the present review article we summarize mainly histochemical work dealing with descending bulbospinal serotonin neurons which also express a number of neuropeptides, in particular substance P and thyrotropin releasing hormone. Such neurons have been observed both in rat, cat and monkey, and may preferentially innervate the ventral horns of the spinal cord, whereas the serotonin projections to the dorsal horn seem to lack these coexisting peptides. More recent studies indicate that a small population of medullary raphe serotonin neurons, especially at rostral levels, also synthesize the inhibitory neurotransmitter gamma-amino butyric acid (GABA). Many serotonin neurons contain the glutamate synthesizing enzyme glutaminase and can be labelled with antibodies raised against glutamate, suggesting that one and the same neuron may release several signalling substances, causing a wide spectrum of post- (and pre-) synaptic actions.
The effects of reserpine treatment (10 mg/kg, i.p.) on the content of neuropeptide Y-like immunoreactivity and catecholamines were compared with the levels of mRNA coding for neuropeptide Y, tyrosine hydroxylase and phenylethanolamine N-methyltransferase in rat sympathetic neurons and adrenal gland. A reversible depletion of neuropeptide Y-like immunoreactivity was observed in the right atrium of the heart, kidney and masseter muscle, while the immunoreactive neuropeptide Y content in the stellate and lumbar sympathetic ganglia and its axonal transport in the sciatic nerve increased following reserpine. The increase in the stellate ganglion was maximal at 48 h and absent 9 days after reserpine treatment. The expression of neuropeptide Y mRNA and tyrosine hydroxylase mRNA in both the stellate and the superior cervical ganglion increased earlier than the neuropeptide Y content, with a clear cut two-fold elevation at 24 h after reserpine. The increase in both mRNAs in the superior cervical ganglion and the depletion of neuropeptide Y, but not of noradrenaline, in terminal areas was prevented after pretreatment both with a nicotinic receptor antagonist (chlorisondamine) and with surgical preganglionic denervation. A marked (75-90%) depletion of neuropeptide Y-like immunoreactivity and adrenaline in the adrenal gland, concomitant with 3-4-fold increases in neuropeptide Y mRNA and tyrosine hydroxylase mRNA expression, was present at 24 h after reserpine treatment. Also in the adrenal gland, there was a reversal of the reserpine-induced increase in neuropeptide Y mRNA and tyrosine hydroxylase mRNA and depletion of neuropeptide Y and adrenaline following splanchnic denervation. Pharmacological, ganglionic blockade prevented the depletion of neuropeptide Y and the increased expression of neuropeptide Y mRNA, but not fully, the tyrosine hydroxylase mRNA elevation. In addition, a marked decrease in phenylethanolamine N-methyltransferase mRNA levels was noted after reserpine. This decrease was reversed by denervation and by ganglionic blockade. Denervation alone led to a small but significant decrease in all mRNAs examined both in the superior cervical ganglion and the adrenal medulla. The present data suggest that the depletion of neuropeptide Y-like immunoreactivity in sympathetic nerves and in the adrenal gland after reserpine is associated with a compensatory increase in neuropeptide Y synthesis and axonal transport, most likely due to increased nicotinic receptor stimulation. Whereas the reserpine depletion of neuropeptide Y in both sympathetic nerves and adrenal gland is related to neuronal activation, adrenal but not nerve terminal depletion of catecholamines can be prevented by the ganglionic blocker chlorisondamine.4+e difference in effect of pharmacological ganglionic
The ventral mesencephalons of hamster, guinea pig, cat, monkey, and several humans with and without the diagnosis of schizophrenia were analyzed with in situ hybridization and immunohistochemistry. Extensive codistribution of cholecystokinin mRNA and tyrosine hydroxylase [L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] mRNA was observed in cats and monkeys as well as in all five human subjects with the diagnosis of schizophrenia and in two out of five control brains. Double labeling revealed coexistence of the two markers in cat, monkey, and human. No cholecystokinin mRNA or cholecystokinin peptide was detected in the substantia nigra/ventral tegmental area of the hamster or guinea pig, even after acute and chronic neuroleptic treatment.
A double-labeling immunofluorescence colocalization technique was used to examine the extent of coexistence of somatostatin (SOM)-like immunoreactivity with neuropeptide Y (NPY)-, tyrosine hydroxylase (TH)- and vitamin D-dependent calcium binding protein (D-CaBP)-like immunoreactivities in neurons of the rat main olfactory bulb. SOM-like immunoreactivity (SOM-I) was distributed within restricted populations of periglomerular neurons and deep short-axon cells, and rarely within superficial short-axon cells at the glomerular layer/external plexiform layer (GL/EPL) border region. Double-labeling analysis revealed that all of the SOM-I deep and superficial short-axon cells also contained NPY-I. Colocalization of SOM-I and TH-I or of SOM-I and D-CaBP-I was infrequently observed within periglomerular neurons. The rare SOM-I short-axon cells at the GL/EPL border always exhibited D-CaBP-I. These results demonstrate virtual complete coexistence of SOM and NPY in short-axon neurons of the main olfactory bulb. With a few exceptions, however, bulbar SOM neurons appear to constitute subclasses of periglomerular cells immunohistochemically distinct from those containing TH or D-CaBP.
The cellular localization of neurons expressing cholecystokinin (CCK) and tyrosine hydroxylase (TH) mRNAs was analysed in rat ventral mesencephalon using in situ hybridization techniques with both complementary DNA and synthetic oligonucleotide probes. Cell bodies distributed throughout the substantia nigra, ventral tegmental area, interfascicular nucleus, midline raphe nuclei, and central and ventral periaqueductal grey matter were found to contain CCK mRNA or TH mRNA as indicated by high densities of grains overlying the perikarya. The in situ hybridization technique was combined with immunocytochemistry on the same tissue section to localize the peptide or enzyme within its respective mRNA-containing somata. In addition, the presence of TH immunoreactivity was demonstrated within cell bodies labeled for CCK mRNA and immunostaining for CCK was detected within TH mRNA-containing neurons. In the medial geniculate nucleus a strong labeling for CCKmRNA was observed, in spite of the fact that so far no CCK-like immunoreactivity has been demonstrated in perikarya in this nucleus. The specificity of the probes was verified by RNA blot hybridization. These results confirm recent double-labeling immunocytochemical studies and further characterize the coexistence of CCK and TH at the level of their mRNAs as well as their post-translational products in a large population of mesencephalic dopamine neurons known to project to forebrain areas.
The colocalization of serotonin (5-hydroxytryptamine; 5-HT) and gamma-aminobutyric acid (GABA) in the ventral aspect of the rat medulla oblongata was studied using antibodies directed against 5-HT and GABA. Although 5-HT- and GABA-immunoreactive cell bodies were observed over the entire rostral-caudal extent of the ventral medulla, the colocalization of these two classical neurotransmitters in single cells was, for the most part, limited to a region that corresponds anatomically to nucleus raphe magnus/nucleus paragigantocellularis. Schematic drawings showing the distribution of 5-HT/GABA cell bodies in the ventral medulla are provided.
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.
Double-labeling combined with elution-restaining immunofluorescence techniques were used to analyze the extent of coexistence among the peptides cholecystokinin (CCK), peptide histidine-isoleucine (PHI)/vasoactive intestinal polypeptide (VIP), substance P and the catecholamine-synthesizing enzyme tyrosine hydroxylase in neurons of the supramammillary region and mesencephalon of the rat. Approximately 50% of the PHI/VIP-containing perikarya and about 25% of the CCK-positive cell bodies in the supramammillary region exhibited coexistence of both peptides. Only a very minor portion of these double-labeled neurons were also found to contain immunostaining for tyrosine hydroxylase (indicative of dopamine in these cells). A low percentage of the neurons contained the enzyme plus either CCK- or PHI/VIP-like immunoreactivity. A low proportion of the tyrosine hydroxylase-positive neurons in this region contained substance P-like immunoreactivity and vice versa. In other areas, small numbers of neurons in periventricular and periaqueductal regions were found to be immunostained for CCK, PHI/VIP and tyrosine hydroxylase. Single examples of triple-labeled (CCK-PHI/VIP-TH) somata were infrequently observed in the ventral tegmental area. These data provide further evidence of peptide/peptide and peptide/monoamine coexistence in the central nervous system. The demonstration of CCK-PHI/VIP colocalization (possibly including a minor dopaminergic component) and of substance P and tyrosine hydroxylase coexistence within neurons of the supramammillary region, which has widespread projections to many areas of the forebrain, suggests that these neuropeptides may coexist in some of these pathways and perhaps be co-released in several different regions of the brain.
The adrenal gland of the rat was analysed with immunohistochemistry and antisera to neuropeptide tyrosine, to the catecholamine-synthesizing enzymes tyrosine hydroxylase, phenyl-ethanolamine-N-methyltransferase, and to acetylcholinesterase and with in situ hybridization using a nick-translated 280 base pair deoxyribonucleic acid probe coding for exon 2 of the rat neuropeptide tyrosine gene. Neuropeptide tyrosine-like immunoreactivity was observed in three structures: chromaffin cells, medullary ganglion cells and nerve fibers. The chromaffin cells were of both the noradrenaline- and adrenaline-type. The ganglion cells did not seem to contain any catecholamine-synthesizing enzymes but exhibited a strong immunoreaction for acetylcholinesterase. They were thus in all probability cholinergic neurons. In situ hybridization using the nick-translated deoxyribonucleic acid probe to rat neuropeptide tyrosine messenger ribonucleic acid revealed a very high-grain density over the ganglion cells, a moderate density over the chromaffin cells and a low background over cortex, in agreement with the immuno-histochemical demonstration of neuropeptide tyrosine-like immunoreactivity both in chromaffin and ganglion cells. The intense neuropeptide tyrosine-like immunoreactivity and low content of neuropeptide tyrosine messenger ribonucleic acid suggest that the chromaffin cells have fairly large peptide stores but that the peptide turnover is low. In contrast, the ganglion cell bodies seem to contain low amounts of neuropeptide tyrosine-like immunoreactivity but exhibit a high neuropeptide tyrosine synthesis rate. Preliminary studies with the amine-depleting drug reserpine revealed an increase in messenger ribonucleic acid both in ganglion cells and medullary cells. In the chromaffin cells the highest activity was seen 3 and 4 days after injection, and the levels were down to normal after 8 days. The present findings demonstrate neuropeptide tyrosine synthesis and storage in two cell populations in the adrenal medulla. In situ hybridization with its cellular resolution can provide information on possible differential effects of drugs and experimental procedures on these two neuropeptide tyrosine stores.
The ventral aspect of the medulla oblongata of colchicine-treated rats was examined immunohistochemically using mouse monoclonal antibodies raised against somatostatin (SOM) and rabbit polyclonal antibodies to methionine enkephalin (ENK). Numerous perikarya showed positive immunostaining for both antisera. For the most part, the double-labelled cells were located (1) along the ventrolateral surface in a region that corresponds to nucleus paragigantocellularis, (2) in the region of nucleus gigantocellularis-nucleus raphe magnus and (3) in a discrete area just above the inferior olivary nucleus. In an attempt to determine the projection sites of the SOM/ENK somata, the retrogradely transported fluorescent dye Fluoro-Gold was injected into either the nucleus tractus solitarii (NTS) or the upper part of the thoracic spinal cord. SOM/ENK cells in all 3 regions were labelled by dye administered into the spinal cord whereas only those SOM/ENK cells located in nucleus paragigantocellularis were stained by dye microinjected into NTS. This is the first evidence of a SOM/ENK projection from the ventral medulla to either the spinal cord or NTS.
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.
Fluorescence immunohistochemistry was used to analyze the medulla oblongata of colchicine-treated rats that had been incubated with guinea pig antibodies to serotonin (5-HT) and either rabbit or sheep antibodies to glutamic acid decarboxylase (GAD). Numerous cells in the rostral ventrolateral medulla in the region of nucleus raphe magnus were immunostained for either 5-HT or GAD. A substantial number of neurons showed positive immunoreactivity for both substances, and were most frequently observed in the lateral aspect of nucleus raphe magnus. In addition, a number of the 5-HT/GAD-containing neurons were retrogradely labelled with Fast blue dye that had been injected into the thoracic spinal cord. This work provides evidence for colocalization of the classical neurotransmitters 5-HT and GABA in single cells of the ventral medulla oblongata, some of which project to the spinal cord.
A double-label immunofluorescence technique was used to demonstrate that immunoreactivities for the functionally antagonistic neuropeptides enkephalin and cholecystokinin octapeptide (CCK) are co-localized within individual neurons and processes in discrete areas of rat midbrain and forebrain. Coexistence was most prominent within varicose pericellular axons extending from the periaqueductal gray matter to a field overlying the medial lemniscus, axons and terminal-like puncta in the central medial, paracentral, interanterodorsal and ventral anterior thalamic nuclei, and perikarya and proximal axonal fragments in layers II and III of neo- and allocortex, and in the anterior olfactory nucleus. The former two systems of axons lie in areas of spinothalamic tract termination. These data suggest that some of the antagonism of opioid analgesia by CCK occurs at the synaptic level in nociceptive areas of brain-stem and thalamus where CCK and enkephalin are co-localized and presumably co-released.
Neuropeptide tyrosine (neuropeptide Y, NPY) is a potent vasoconstrictor with a wide distribution in the central and peripheral nervous systems. Here we show that high levels of rat NPY mRNA are also found in peripheral blood cells, bone marrow, lung, and spleen. Furthermore, radioimmunoassay revealed high levels of NPY-like peptide in these tissues. In mice, the levels of splenic NPY mRNA and immunoreactive peptide differed extensively between strains and were greatly elevated in several strains (NZB, NZBxW, and BXSB) that develop a disease resembling human systemic lupus erythematosus. Like the rat, the NZB mouse showed a high content of NPY mRNA in peripheral blood cells and bone marrow. Immunohistochemical staining revealed NPY-like immunoreactivity in large cells morphologically identifiable as megakaryocytes in rat bone marrow and in the spleen of the NZB mouse strain. Expression of NPY mRNA in megakaryocytes in rat bone marrow and NZB mouse spleen was confirmed by in situ hybridization. These results indicate that NPY is synthesized in megakaryocytes, implying that NPY can be released from platelets and function as a vasoconstrictor during blood-vessel damage. In addition, the increase in splenic NPY in certain autoimmune mouse strains adds to the list of abnormalities associated with these strains.
The projection of the substantia nigra-ventral tegmental area (SN-VTA) to the ipsilateral and contralateral caudate-putamen was studied with double-labeling fluorescence techniques in the albino rat. By combining glyoxylic acid histofluorescence with retrograde fluorescence tracers, we were able to determine that 93% of the minor (1-2%) contralateral mesostriatal pathway is catecholaminergic. In addition, combined immunofluorescence and retrograde fluorescence tracer studies showed that 50% of the crossed mesostriatal pathway also arises from cholecystokinin-containing neurons. These results provide evidence for crossed catecholamine- and peptide-containing pathways in the mesostriatal system which is part of the 'prefrontal system' that links the prefrontal cortex through the caudate-putamen, with the thalamus and tectum of each hemisphere.
In the present immunohistochemical study the occurrence and distribution of CCK-immunoreactive neurons were analyzed in the brain, spinal cord and sensory ganglia using sequence specific antisera. Thus, antibodies directed towards the C-terminal portion of CCK-33, to the N-terminal portion of CCK-8 and to the mid portion of CCK-33 as well as monoclonal antibodies were used. For comparison antisera raised against calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH) and 5-hydroxytryptamine (5-HT) were used. Untreated, colchicine treated, 6-hydroxydopamine (6-OH-DA) treated and ibotenic acid treated rats were analyzed. The results indicate that most CCK systems in the rat central nervous system contain genuine CCK. These include, for example, the hippocampal formation, the hypothalamus, several subcortical forebrain areas, the ventral mesencephalon, nucleus tractus solitarii, some neurons in the ventral medulla oblongata as well as local and possibly descending neurons in the spinal cord. An exception was primary sensory neurons in which CCK-like immunoreactivity (LI) could only be demonstrated with C-terminally directed antisera and probably represents cross-reactivity with CGRP or a similar peptide. The central branches of such primary afferents were found both in the dorsal vagal complex, in the spinal trigeminal nucleus and in the dorsal horn of the spinal cord. Special attention was focused on CCK-LI in mesencephalic dopamine neurons and in their projection areas including nucleus accumbens, tuberculum olfactorium and particularly the caudate nucleus. In the latter structure CCK-LI exhibited a heterogenous pattern probably representing fibres of different types and origin. Thus, CCK-LI coexists with dopamine in two anatomically and morphologically distinguishable systems, one located in the periventricular area, increasing in size in the caudal direction to occupy most of the cauda, and a second system consisting of very fine dots in the medial half of the caudate nucleus. These two fibre types disappeared after 6-OH-DA treatment. A third system consisted of strongly fluorescent patches distributed at all levels of the caudate nucleus, mainly in its medial half. A diffuse, weakly fluorescent network of CCK-positive fibres was also found over the entire caudate nucleus. The latter two systems did not disappear after 6-OH-DA. Finally, local CCK-positive cell bodies were seen in small numbers, mainly in the ventral aspects of the caudate nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)