Localization of allatostatin-immunoreactive material in the central nervous system,stomatogastric nervous system,and gut of the cockroach Blattella germanica

Immunoreactivity against peptides of the allatostatin family having a typical YXFGL-NH₂ C-terminus has been localized in different areas of the central nervous system, stomatogastric nervous system and gut of the cockroach Blattella germanica. In the protocerebrum, the most characteristic immunoreactive perikarya are situated in the lateral and median neurosecretory cell groups. Immunoreactive median neurosecretory cells send their axons around the circumesophageal connectives to form arborizations in the anterior neuropil of the tritocerebrum. A group of cells in the lateral aspect of the tritocerebrum project to the antennal lobes in the deutocerebrum, where immunoreactive arborizations can be seen in the periphery of individual glomeruli. Nerve terminals were shown in the corpora allata. These terminals come from perikarya situated in the lateral neurosecretory cells in the pars lateralis and in the subesophageal ganglion. Immunoreactive axons from median neurosecretory cells and from cells positioned in the anteriormost part of the tritocerebrum enter together in the stomatogastric nervous system and innervate foregut and midgut, especially the crop and the valve between the crop and the midgut. The hindgut is innervated by neurons whose perikarya are located in the last abdominal ganglion. Besides immunoreactivity in neurons, allatostatin-immunoreactive material is present in endocrine cells distributed within the whole midgut epithelium. Possible functions for these peptides according to their localization are discussed. Arch. Insect Biochem. Physiol. 37:269–282, 1998. © 1998 Wiley-Liss, Inc.     

Ecdysteroid binding sites localized by autoradiography in the central nervous system of precommitment fifth-stadium Manduca sexta larvae

Summary Brains and subesophageal ganglia from day 3.5 fifth stadium larvae of Manduca sexta were incubated in vitro with 4 nM tritiated ponasterone A, a 20-hydroxyecdysone analog, to determine whether uptake and specific binding of ecdysteroids occur at a cellular level. These tissues, which were taken just prior to the commitment peak in the hemolymph-ecdysteroid titer, showed saturable uptake of ³H-ponasterone A after 40–60 min of incubation. Uptake was blocked by the addition of 400 nM unlabelled ponasterone A, or of 500 nM or 1000 nM 20-hydroxyecdysone. RH 5849, a synthetic 20-hydroxyecdysone agonist with a long half-life, for which ecdysteroid receptors have low affinity, also reduced ponasterone A uptake at a concentration of 10 M. Autoradiographs of 4 m sections of brains revealed distinct nuclear concentrations of silver grains over cell populations in the pars intercerebralis, pars lateralis, and ventral tritocerebrum. Nuclear labelling was also found in many small cells around the mushroom bodies and the neuropil, and between the inner and outer larval optic lobes. Nuclear labelling of cells in the subesophageal ganglion was observed in the fronto-medial and lateral regions, in small cells around the neuropil, and caudally in a few large neurons. In addition to cells with nuclear labelling, both brains and ganglia at this development stage contained cells with exclusively cytoplasmic or both nuclear and cytoplasmic labelling. None of these apparent binding sites were observed in the competition experiments, suggesting that the binding is specific.     

Localization of neurokinin B in the central nervous system of the rat.

The distribution of neurokinin B (NKB) was determined by immunocytochemistry with antisera directed toward its amino terminus. Immunoreactive perikarya were detected in the main and accessory olfactory bulbs, cortical regions, the olfactory tubercle, the bed nucleus of the stria terminalis, the diagonal band of Broca, the nucleus accumbens, the septum, the neostriatum, several hypothalamic nuclei, the superior colliculus, the central gray, the substantia nigra, the medullary reticular formation, and the external cuneate nucleus. The distribution of NKB-containing perikarya revealed by immunocytochemistry was similar to the distribution of protachykinin B-containing cells previously visualized by in situ hybridization. Immunoreactive nerve fibers and terminals were detected in all major subdivisions of the brain. The levels of NKB measured by radioimmunoassay were highest in the hypothalamus. The distribution of NKB in the rat brain was similar to the distribution of substance P; however, there were several regions where the two distributions were clearly different.     

Localization of subspecies of protein kinase C in the mammalian central nervous system

Activation of protein kinase C (PKC) is regulated by dual second messengers; diacylglycerol (DG) produced by receptor mediated hydrolysis of phosphatidylinositol and Ca²⁺ which is released by inositol 1,4,5-triphosphate (IP3) from intracellular stores in the endoplasmic reticulum. In the mammalian central nervous system, available evidence suggests that PKC plays a prominent role in the processing of neuronal signals and in the short-term or long-term modulation of synaptic transmission. This enzyme is a member of a family consisting of at least eight subspecies, , βI, βII, γ, δ, , ζ and η. The homologous structure of each subspecies makes difficult resolution of the enzymological properties of the enzyme. The distinct functional roles of PKC subspecies in mammalian tissues have been elucidated by defining the localization of each subspecies. We identified -, βI-, βII- and γ-PKC subspecies in the rat brain by in situ hybridization and by light and electron microscopic immunohistochemistry, using antibodies specific for each subspecies. Most immunoreactions of the , βI, βII and γ subspecies were evident in neurons and there were few, if any, in glial cells. In this article, we summarize known cellular and subcellular localizations of PKC subspecies in mammalian CNS and some aspects of current studies in neuronal functions regulated by this enzyme are discussed.     

Method of quantitative assessment of morphological changes in the central nervous system]

The author present a variant of quantitative assessment of the degree of morphological changes in the central nervous system neurons. It is suggested that the following groups of the changed neurons should be distinguished: swollen neuron with the initial manifestations of breaking large tigroid lumps into smaller ones; swollen neuron with marked phenomena of breaking large tigroid lumps into smaller ones and initial phenomena of hypochromatosis; swollen neuron with total tigrolysis with hyper- and hypochromatosis; dehydrated hyperchromic neuron; vacuolized neuron; contracted atrophic neuron; perished neuron. Each of the mentioned groups is given a mark, characterizing the degree of morphological changes. A formula for the assessment of the degree of morphological changes for individual formations and zones of the central nervous system is suggested.     

Localized recrudescence of Toxoplasma infections in the central nervous system of immunocompromised mice assessed by in vivo bioluminescence imaging

Reactivation of infection in the central nervous system (CNS) with the opportunistic parasite Toxoplasma gondii is a major concern in chronically infected immunocompromised individuals. Yet, the pathophysiology associated with recrudescence of infection remains poorly characterized. The onset of acute reactivated Toxoplasma encephalitis in the murine model was assessed using bioluminescence imaging as a spatio-temporal indicator. An uneven distribution of recrudescence of infection in the CNS was found. Foci of recrudescence after immunosuppression were most commonly located in frontal and parietal cortex, whereas little infection was found in the cerebellum. Recrudescence was also more common in grey matter than in white matter. Pathology was exacerbated in mice deficient in interferon gamma receptors (IFN gamma R(-/-)) corroborating the importance of interferon gamma (IFN gamma) for control of CNS infection. Analysis of parasitic foci identified abundant leukocyte infiltration (CD45+, CD4+, CD8+, F4/80+ cells) in the vicinity of replicating parasites and microvasculature. This is the first report that addresses the suborganic localization of acute Toxoplasma encephalitis in the murine model. Collectively, the findings suggest that the localization of reactivation foci in the CNS, in conjunction with immune responses, influences the outcome of acute reactivated Toxoplasma encephalitis.     

Localization of NADPH diaphorase in the central nervous system of the bivalve mollusc Cristaria tuberculata

By histochemical and electron histochemical methods, NADPH-diaphorase was discovered in neurons and their processes of all ganglia of the central nervous system (CNS) of Cristaria tuberculata. Small cells predominated among neurons containing NADPH-diaphorase. Ultrastructural localization of the enzyme was detected on the perinuclear membrane and membranes of endoplasmic reticulum, cytoplasmic granules and cytosol. In the majority of cells, the reaction product was commonly found in cytoplasmic granules-cytosomes. We studied peculiarities of synaptic contacts between nitrogen oxide synthesizing neurons and their processes. In active synaptic areas, a sediment was discovered on the internal surface of pre- and postsynaptic membranes.     

Localization of CRF immunoreactivity in the central nervous system of three vertebrate and one insect species

Summary By use of a specific antiserum against synthetic ovine corticotropin-releasing factor (CRF) in the peroxidase-antiperoxidase (PAP) immunocytochemical procedure (Vandesande and Dierickx 1976), CRF-like antigenic determinants were demonstrated in the central nervous system of a human fetus, the Wistar rat, the frog Rana ridibunda, and the American cockroach Periplaneta americana. The immunoreactive CRF-producing cells occur mainly in the nucleus paraventricularis of the rat, while in Rana ridibunda these cells occur in the nucleus praeopticus. Immunoreactive CRF-containing fibres were also visualized. Very clear CRF-immunoreactive products were observed in the brain as well as the corpora cardiaca (CC) and corpora allata (CA) of the cockroach Periplaneta americana. ACTH-immunoreactivity was also demonstrated in the brain-CC-CA complex of this insect. Double immunohistochemical staining (Vandesande 1983) also revealed that both the CRFand ACTH-like substances occur in different neurosecretory neurons and nerve fibres. These results suggest that the antigenic determinants of CRF are very similar in vertebrates and insects bespeaking their very long evolutionary history.     

Localization of urotensin I- and corticotropin-releasing factor-like immunoreactivity in the central nervous system of Catostomus commersoni

The distribution of urotensin I (UI) and corticotropin-releasing factor (CRF) immunoreactive (IR) structures was studied in the central nervous system (CNS) of the white sucker using the peroxidase-antiperoxidase immunocytochemical procedure. The close sequence homology between both peptides resulted in a high degree of crossreactivity. This was resolved by saturating the antisera solutions with heterologous antigens and specificity tests were done by adding excess of homologous peptides. UI immunoreactivity was seen in all of the identifiable caudal spinal cord neurosecretory cells, in their processes projecting to the urophysis, in thin beaded fibres coursing along the spinal cord, in brain stem, hypothalamus, proximal pars distalis and, especially, in the telencephalon. Some IR-UI specific and IR-CRF specific parvocellular neurons were also identified in the caudo-ventral tuberal region and ventral telencephalon. The IR-CRF was mainly present in parvocellular and magnocellular perikarya of the nucleus preopticus and in the preoptic-neurohypophysial pathway. Dense networks of IR-CRF reacting beaded fibres were also located in the lateral and posterior recessus nuclei. In the pituitary, IR-CRF fibre bundles were seen mainly in the neurointermediate lobe and in the rostral pars distalis. The cells of origin of the extraurophyseal system of IR-UI fibres in the sucker CNS have not been identified. The distribution of CRF immunostaining correlates well with the documented knowledge of CNS structures involved in the control of ACTH secretion in the goldfish. The probability of the occurrence of two UI-CRF related molecules, or of two different forms resulting from a common precursor molecule, forming two separate neuronal systems in the sucker CNS seems likely.     

A silver impregnation technique for the study of steroid receptors in central nervous system tissue prepared for autoradiography

The commonly used silver stains were found to be unsatisfactory for nervous tissue processed for autoradiography. A silver impregnation procedure for central nervous system tissues prepared for the autoradiographic study of steroid receptors is described. The procedure is a combination of several silver and reticular strains made up in solutions containing dimethylsulfoxide. The technique clearly distinguishes perikarya of neurons, brain nuclei and fiber tracts without substantial loss of silver grains, and thus greatly facilitates the identification of steroid receptor nuclei at all levels of the central nervous system.     

Localization of NADPH-diaphorase and choline acetyltransferase in the central nervous system of the bivalve mollusk Mactra sulcatoria

The presence of NADPH-diaphorase and choline acetyltransferase (ChAT) in all ganglia of the Mactra sulcatoria was demonstrated by histochemical and electron histochemical methods. Pecularities of cholinergic and nitrergic neurons localization were revealed in nervous ganglia, and their relative content there was estimated. It was established that in reaction to ChAT only large neurons were marked. Ultrastructural localization of NADPH-diaphorase and ChAT was determined in neurons and neuropile. The data obtained testify that NADPH-diaphorase and ChAT are located in different types of nervous cells. The opportunity of functional cooperation in activity of cholinergic and nitrergic systems in mollusks is discussed.     

Analgesia induced by N-acetylserotonin in the central nervous system

The relationship between N-acetylserotonin (NAS) in the central nervous system (CNS) and responses to pain was investigated. Using the rat tail-flick model, we initially replicated the work of others showing that intraventricular (IVC) injection of a dipeptide structurally similar to both NAS and serotonin was capable of inducing analgesia in the rat. We then showed that IVC-NAS, but not serotonin elicited analgesia in much the same manner as the dipeptide. This effect proved to be very specific as it required the presence of both an acetyl group on the terminal side chain amine as well as a hydroxyl group on the C-5 position of the indole ring. Substitution of the C-5 hydroxyl by a methoxyl group (melatonin) abolished the analgesic effect. Similarly, removing the N-acetyl substitution (serotonin) also eliminated the analgesia. IVC injection of highly specific antiserum to NAS induced hyperalgesia. Furthermore, an interaction was found between NAS and opiate systems. We demonstrated that while naloxone, the opiate antagonist, has no hyperalgesic properties of itself, it did counteract the analgesia induced by NAS. Similarly, NAS antiserum reversed the analgesia induced by the opiate morphine. This work provides evidence that NAS is an endogenously active substance within the CNS pain network.