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S J Watson

Publications and source records attributed to S J Watson.

At least 307 records · Page 17Linked to original sources
PubMed1977

beta-Lipotropin: localization of cells and axons in rat brain by immunocytochemistry.

Using specific antisera to human beta-lipotropin, we have visualized cells and axons with beta-lipotropin-like immunoreactivity in rat brain and pituitary. The beta-lipotropin so localized is well delineated and contained in the cytoplasm of cells and in beaded axons. Areas of greatest beta-lipotropin content are hypothalamus (with cell bodies in the medial basal hypothalamus and arcuate regions), periventricular nucleus of the thalamus, ansa lenticularis, zona compacta of the substantia nigra, medial amygdaloid nucleus, zona incerta, periaqueductal central gray area, locus ceruleus, and a few fibers in the reticular formation. The question of the exact relationship of beta-lipotropin and methionine-enkephalin remains open, because some brain areas contain both substances and some areas contain only one or the other.

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PubMed1975

Histofluorescence in the unperfused CNS by cryostat and glyoxylic acid: a preliminary report.

This paper describes an adaptation of glyoxylic acid histofluorescence to cryostat sections. The technique utilizes unperfused frozen brain, cryostat sectioning, immersion in 2% glyoxylic acid solution, warm-air drying, and exposure to hot glyoxylic acid gas. Fine, well-localized catecholamine histofluorescence is produced in cells, axons, and terminals. Both the anatomical localization and pharmacological specificity of the fluorescence conform to traditional catecholamine literature. The technique has the advantage of overcoming preservation and sectioning problems associated with the Vibratome. Because unperfused brain is used, alternate sections can be prepared for a variety of anatomical demonstrations or biochemical assays.

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PubMedDate not supplied

Cryostat technique for central nervous system histofluorescence.

This paper offers a technique for obtaining monoamine histofluorescence in the CNS by means of formaldehyde perfusion followed by cryostat sectioning. No freeze-drying is involved. Cryostat sections are exposed to formaldehyde vapor to complete the fluorophore formation. The fluorescence thus obtained is bright, well localized, and does not require loading the animals with precursors. The anatomical distribution of the pathways is identical to that obtained with the classical technique. Furthermore, the fluorescence is reversible by sodium borohydride, and exhibits the expected changes in intensity with pharmacological manipulations. The sections can be exposed to a cold aqueous medium for as long as 15 min with minimal diffusion of fluorophore; this suggests potential for combining monoamine histofluorescence with other visualization techniques.

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PubMedDate not supplied

Frequency of neuropathology in a brain bank from a long-term, domiciliary population.

Postmortem analysis of brain chemistry and anatomy in the study of psychiatric disorders has enjoyed renewed interest recently. There are myriad difficulties in establishing a brain bank, including proper diagnosis and confounding neuropathology. These difficulties may become more pronounced in a long-term domiciliary facility. In order to begin to address neuropathologic considerations, we performed neuropathological examinations on each patient included in our bank of 20 brains. Forty-five per cent of all patients had significant and unexpected neuropathology. Selection of patients to be included in postmortem studies requires careful screening to enhance accurate neuropathological assessment.

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PubMedDate not supplied

Dynorphin is located throughout the CNS and is often co-localized with alpha-neo-endorphin.

The opioid peptide dynorphin has been described as widely distributed in CNS when measured by RIA. Our previous immunohistochemical studies have only demonstrated dynorphin cells as those containing AVP. We now report the specific localization of dynorphin throughout the neuraxis. Further, dynorphin and alpha-neo-endorphin have been co-localized to the same magnocellular neurosecretory cells in hypothalamus. We report agreement with the findings of others and extend them to include a cell group in dorsomedial hypothalamus, further strengthening the association between dynorphin and alpha-neo-endorphin.

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PubMedDate not supplied

Visualization of opiate receptors and opioid peptides in sequential brain sections.

Autoradiographic and immunocytochemical studies were carried out on adjacent sections from formaldehyde-perfused rat brains in order to directly correlate the distribution of opiate receptors and opioid peptides. Perfusion fixation of the brains resulted in a partial loss of specific [3H]naloxone binding with essentially no change in the pharmacological properties of the remaining sites. When the distribution of sites was compared to that of enkephalin immunoreactivity in adjacent sections, striking correlations were observed in a number of areas throughout the neuraxis. Adjacent section autoradiography-immunocytochemistry should provide a useful tool for relating the anatomical distribution of opiate receptor subtypes to different opioid peptide neuronal systems.

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PubMedDate not supplied

Gamma-melanotropin response to ovine corticotropin releasing factor in normal humans.

Plasma gamma-melanotropin was measured by a gamma 3MSH-specific radioimmunoassay before and after a single bolus intravenous infusion of ovine corticotropin releasing factor (oCRF; 0.1 microgram/kg) in seven normal men. A significant increase of gamma 3MSH was observed 15 minutes post-oCRF infusion, which paralleled a similar increase in plasma cortisol. Gel filtration chromatography revealed that the observed increase was attributable to elevations of 9K and 4K forms of gamma 3MSH immunoreactivity. Affinity chromatography demonstrated that the majority of gamma 3MSH immunoreactivity in human plasma is glycosylated. As the smaller forms of gamma 3MSH are felt to have endocrine activity at the adrenal cortex, these changes may be physiologically relevant.

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PubMedDate not supplied

Dynorphin immunocytochemistry in the rat central nervous system.

The distribution of dynorphin in the central nervous system was investigated in rats pretreated with relatively high doses (300-400 micrograms) of colchicine administered intracerebroventricularly. To circumvent the problems of antibody cross-reactivity, antisera were generated against different portions as well as the full dynorphin molecule (i.e., residues 1-13, 7-17, or 1-17). For comparison, antisera to [Leu]enkephalin (residues 1-5) were also utilized. Dynorphin was found to be widely distributed throughout the neuraxis. Immunoreactive neuronal perikarya exist in hypothalamic magnocellular nuclei, periaqueductal gray, scattered reticular formation sites, and other brain stem nuclei, as well as in spinal cord. Additionally, dynorphin-positive fibers or terminals occur in the cerebral cortex, olfactory bulb, nucleus accumbens, caudate-putamen, globus pallidus, hypothalamus, substantia nigra, periaqueductal gray, many brain stem sites, and the spinal cord. In many areas studied, dynorphin and enkephalin appeared to form parallel but probably separate anatomical systems. The results suggest that dynorphin occurs in neuronal systems that are immunocytochemically distinct from those containing other opioid peptides.

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PubMedDate not supplied

Some perspectives on monoamine-opioid peptide interaction in rat central nervous system.

Light microscopic immunocytochemistry was employed to investigate possible sites of interaction between the endogenous opioid peptides and monoamines in the rat central nervous system. The opioid and related peptides examined included beta-endorphin (beta-END), alpha-MSH (alpha-MSH) and leucine-enkephalin (Leu-ENK). The monoamines were examined using antisera generated against tyrosine hydroxylase, dopamine-beta-hydroxylase as well as serotonin. Due to the long-tract nature of the central monoamine projections as well as beta-END/alpha-MSH fiber systems, serial section analyses were performed utilizing parasagittal brain sections. Many areas rich in both the monoamines as well as opioid peptides were investigated. These included several thalamic and hypothalamic nuclei, several limbic structures, mesencephalic periaqueductal gray, brain stem noradrenergic cell groups and their rostral projections, the dopaminergic nigrostriatal system, and the serotonergic raphe nuclei and their projections. The results suggest a more intimate linkage between the monoamines and the opioid peptides than previously realized. Some of the intricacies of monoamine-opioid peptide interaction, in particular those pertaining to their possible role in pain and analgesia, catalepsy, and neuroendocrine effects are also discussed.

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PubMedDate not supplied

Microcomputer-based three-dimensional reconstruction of in situ hybridization autoradiographs.

A number of software routines were written for the public domain Macintosh-based video-densitometry program, Image, to facilitate in situ hybridization analysis. These routines utilize fiducial marks drilled in unused portions of the brain to rotate high-magnification images of individual sections so that they may be placed in register. The regions of interest within the registered sections are outlined and intermediate sections interpolated to produce a data set representing a three-dimensional volume. This shell is then filled with the original density data obtained with one or more in situ hybridization probes. The final object can be viewed in various degrees of translucency and examined from different angles or computationally resectioned to yield new information concerning activity changes within the region and relationships between reactive sites. These static images can be collected and rapidly displayed as a movie. These routines have been used in this paper to display the differential hybridization of three different mRNA probes in the hypothalamic paraventricular nucleus.

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PubMedDate not supplied

Delta opioid receptor mRNA distribution in the brain: comparison to delta receptor binding and proenkephalin mRNA.

The recent cloning of the mouse delta opioid receptor (Evans et al., 1992; Kieffer et al., 1992) has demonstrated it to be a member of the seven transmembrane G-protein coupled family of neurotransmitter receptors. The present study describes the cellular localization in the central nervous system (CNS) of an mRNA encoding this receptor and compares it with the distribution of delta receptor binding and proenkephalin mRNA using a combination of in situ hybridization and receptor autoradiographic techniques. Delta receptor mRNA was visualized with a cRNA probe (472-903 bp) corresponding to transmembrane domains III-VI of the receptor, while proenkephalin mRNA was labeled with a cRNA probe to exon 3 (139-832 bp). A high level of correspondence was observed between the distribution of delta receptor mRNA and delta receptor binding as defined by the selective ligand [3H]D-Pen2-Pen5-enkephalin. Delta receptor mRNA and binding were expressed in the neocortex, caudate-putamen, nucleus accumbens, olfactory tubercle, diagonal band of Broca, amygdala and the nucleus of the solitary tract. Discrepancies in the distribution of delta receptor mRNA and binding in the olfactory bulb, hippocampus, globus pallidus and substantia nigra pars reticulata, may in part be due to differential receptor synthesis and transport. These results are discussed in relation to the distribution of proenkephalin mRNA and how this may affect our understanding of opioid circuitry in the CNS.

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PubMedDate not supplied

The distribution of dopamine D2 receptor heteronuclear RNA (hnRNA) in the rat brain.

Conventional in situ hybridization methods have been useful in characterizing the anatomical distribution of cells in the central nervous system that express dopamine D2 receptor mRNA. However, due to the large size of the D2 mRNA pool, this method may be insensitive to changes in D2 gene transcription. We have developed a method of hybridizing a 35S-labelled cRNA probe to an intron in the D2 receptor gene in order to measure the amount of primary transcript or heteronuclear RNA (hnRNA) in D2-expressing cells. Introns are found uniquely in hnRNA and are thought to be short-lived intermediates. Thus, monitoring introns could represent a more direct measure of D2 gene transcription. The anatomical distribution of the D2 hnRNA is similar to the distribution of D2 mRNA in the rat brain. D2 heteronuclear RNA was found in the nuclei of cells in the caudate putamen, nucleus accumbens, hippocampus, olfactory tubercle, substantia nigra, ventral tegmental area, and zona incerta. Other regions that contain D2 mRNA, but do not demonstrate intronic signal, include the globus pallidus, prefrontal, cingulate, entorhinal, and piriform cortex, septum, and amygdala. However, these areas have low amounts of D2 mRNA and may contain levels of D2 hnRNA that are below detection. Heteronuclear RNA quantitation by solution hybridization followed by RNase protection was performed on striatum, substantia nigra, cerebral cortex, hippocampus, hypothalamus, and pituitary using a D2 intron 7/exon 8 border probe. These results corroborate the distribution of hnRNA revealed with intronic in situ hybridization. In addition, protection assays were able to detect hnRNA in areas that express low levels of D2 like the cortex, hippocampus and hypothalamus. hnRNA/mRNA ratios calculated from intron/exon border probe protection assays were not equivalent for all the tissue areas studied, indicating that transcription and/or hnRNA half lives may differ between tissues that express D2 receptors. The combined use of intronic in situ hybridization and intron/exon border protection assay as an index of D2 gene transcription and RNA processing provides more information than measuring the mRNA pool alone. It may also prove to be a more useful measure of gene regulation, allowing for evaluation of gene responses to acute treatments.

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