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C Shaw

Publications and source records attributed to C Shaw.

At least 199 records · Page 11Linked to original sources
PubMed1993

A cytochemical study of the nervous system of the proteocephalidean cestode, Proteocephalus pollanicola.

The localization and distribution of cholinergic, serotoninergic and peptidergic nerve elements in the proteocephalidean tapeworm, Proteocephalus pollanicola, have been investigated by enzyme histochemistry, and by an indirect immunofluorescence technique interfaced with confocal scanning laser microscopy. Cholinesterase (ChE) activity was localized in the major components of the central nervous system (CNS) and the peripheral nervous system (PNS), including the innervation of the reproductive structures of the worm. Serotoninergic (5-HT) nerves were found in the paired cerebral ganglia, transverse commissure and in the 10 longitudinal nerve cords. Antisera to 17 mammalian regulatory peptides and the invertebrate peptide FMRFamide have been used to explore the peptidergic nervous system of the worm. The most extensive immunostaining occurred with antisera raised to members of the neuropeptide Y superfamily, namely neuropeptide Y (NPY), peptide YY (PYY) and pancreatic polypeptide (PP). In all cases, intense immunoreactivity was found in numerous cell bodies and fibres of both the CNS and PNS, including the innervation of the reproductive apparatus. FMRFamide antisera stained the same structures to a comparable degree as those raised to the NPY superfamily. Cholinergic and peptidergic elements were much more prevalent within the CNS, while the serotoninergic nerve fibres tended to dominate in the PNS. The overlap obtained in staining patterns for the peptidergic and cholinergic components suggests that there may be a certain amount of co-localization of peptides with small-molecule transmitter substances in the same neurone. Weak staining for the tachykinin, substance P and for calcitonin gene-related peptide (CGRP) was confined to the major longitudinal nerve cords.

Animals↗
PubMed1993

Tachykinin-1 gene products in porcine ocular tissues: evidence for transcriptional and post-translational regulation.

The tachykinin-1 gene in mammals produces structurally-related regulatory peptides, substance P (SP), neurokinin A (NKA), neuropeptide K (NPK) and neuropeptide-gamma. The production of these peptides is regulated by both differential mRNA transcription and post-translational precursor processing. Such processes are known to be highly tissue- and species-specific. In this study, we have examined tachykinin-1 gene expression and precursor processing in porcine ocular tissues by employing specific tachykinin radioimmunoassays coupled with reverse phase HPLC characterization. Optic nerve, cornea, iris, ciliary body, retina, choroid and sclera were micro-dissected from freshly enucleated porcine eyes (n = 10). Following acidified ethanol extraction of tissues, dried extracts were reconstituted and subjected to two radioimmunoassays, one of which is highly specific for intact SP, the other for NKA, NKB, NPK and neuropeptide-gamma. In all tissue extracts except the retina, the molar concentration of SP immunoreactivity was significantly greater than that of NKA. These data would imply expression of both alpha- and beta-preprotachykinin-1 in these ocular tissues. Reverse phase HPLC analysis confirmed the presence of authentic SP and NKA in all tissue extracts. However, in extracts of the retina, NKA immunoreactivity co-eluted with synthetic NPK standard. These chromatographic data suggest differential processing of the beta-preprotachykinin-1 precursor in the retina compared with the other ocular tissues. Thus differential mRNA transcription of the tachykinin-1 gene coupled with differential precursor processing appears to occur in porcine ocular tissues and may be a process of functional significance in the regulation of visual physiology.

Animals↗
PubMed1993

Rabbit pancreatic polypeptide.

1. In almost all studies involving localization or quantitation of regulatory peptides, an essential prerequisite is the generation of specific antisera in rabbits. Despite this almost universal practice, the primary structures of some established regulatory peptides, such as pancreatic polypeptide (PP), of the rabbit, remain unknown. 2. Here we report the full primary structure of PP isolated from extracts of rabbit pancreas. 3. PP immunoreactivity was purified using an antiserum (PP 221) generated to the highly-conserved C-terminal hexapeptide amide of mammalian PP. A single molecular form of rabbit PP was consistently resolved during sequential chromatographic fractionations. 4. Automated Edman degradation established the full primary structure as: APPEPVYPGDDATPEQMAEYVADLRRYINMLTRPRY. The molecular mass derived from this sequence (4196.7 Da), was in full agreement with that determined by mass spectroscopy (4196 Da). The peptide was deemed to be C-terminally amidated due to its full molar crossreactivity with the amide-requiring PP antiserum employed. 5. When compared with all other known mammalian PP sequences, rabbit PP displays three unique substituted sites, Pro at position 3, Glu at position 19 and Val at position 21.

Amino Acid Sequence↗
PubMed1993

High-affinity kainate binding sites in living slices of rat neocortex: characterization and regulation.

We have characterized a high-affinity kainate binding site in in vitro living rat neocortical slices using [3H]kainate. [3H]Kainate labelled at least two binding sites, the higher affinity site with a Kd of 7.1 nM and a Bmax of 71.2 fmol/mg protein. This high-affinity binding site showed a pharmacology consistent with a kainate receptor with competition by kainate and domoic acid, as well as the (RS)-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate antagonist 6-cyano-2,3-dihydroxy-7-nitroquinoxaline. Increases in cellular depolarization induced by 2-h preincubations in veratridine and glutamate led to a significant 55% average decrease in [3H]kainate binding in adult cortex. Similarly, preincubation in kainate led to a significant average 26% decrease in binding. In both instances, Eadie-Hofstee analysis of saturation binding data revealed that the decreased binding reflected changes in receptor number. At different postnatal ages, increases in cellular depolarization significantly decreased binding (< 20 days postnatal age, -86%; > 60 days, -48%). Kainate treatment also significantly decreased binding at all ages (-64% at < 20 days; > 60 days, -18%), with significant differences noted between ages. These age-dependent effects are unlike those previously described for either N-methyl-D-aspartate [Lanius and Shaw (1992) Anat. Rec. 232, 54(A)] or (RS)-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate high affinity receptors [Shaw and Lanius (1992) Devl Brain Res. 68, 225-233].(ABSTRACT TRUNCATED AT 250 WORDS)

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1993

Distribution and immunochemical characteristics of neuropeptide F (NPF) (Moniezia expansa) - immunoreactivity in Proteocephalus pollanicola (Cestoda: Proteocephalidea).

1. Using immunocytochemical techniques and confocal scanning laser microscopy, the proteocephalidean cestode, Proteocephalus pollanicola from Lough Neagh pollan (Coregomus autumnalis) was examined for the presence of the native platyhelminth neuropeptide, neuropeptide F (NPF). 2. An antiserum specific for whole-molecule NPF (1-39) (Moniezia expansa) did not immunostain nerve processes in P. pollanicola. A C-terminally-directed NPF (30-39) (M. expansa) antiserum immunostained nerve fibres and cell bodies of both the central and peripheral nervous systems, including innervation associated with the female reproductive system. 3. The pattern of immunoreactivity was identical to that obtained using antisera to the C-terminal region of mammalian NPY-superfamily peptides and the invertebrate neuropeptide, FMRFamide. 4. Under radioimmunoassay conditions, only the C-terminally-directed NPF antiserum cross-reacted with the P. pollanicola peptide and detected 58.74 ng/g wet weight of NPF-1 R in extracts of the worm. 5. Chromatographic characterisation of P. pollanicola NPF-immunoreactivity indicated an apparent molecular weight of 4400-4700 Da, similar to that of NPF (M. expansa). 6. Further analytical HPLC characterisation identified two molecular forms of P. pallanicoda NPF-immunoreactivity, both of which had different retention times from those of NPF (M. expansa) and NPF (Artioposthia triangulata). 7. These data suggest that P. pollanicola possesses a neuropeptide which is homologous in its C-terminal region to NPF (M. expansa) but differs in its mid- to N-terminal region.

Amino Acid Sequence↗
PubMed1993

Choline acetyltransferase (ChAT) immunoreactivity in a sub-population of mammalian intestinal endocrine cells.

1. The distribution of choline acetyltransferase (ChAT) in rat and guinea-pig intestine has been analysed using an indirect immunofluorescence technique. 2. ChAT immunoreactivity was apparent in nerve fibres and cell bodies of the myenteric and submucous plexus and in fibres throughout the muscle coats and the mucosa. 3. Staining was also evident in a sub-population of mucosal endocrine cells in the small intestine, implying the existence of this enzyme and its product (acetylcholine) in these cells. 4. These data are consistent with previous observations on the distribution of ChAT activity in mammalian intestine.

Animals↗
PubMed1993

Use of specific antisera for the localisation and quantitation of leucokinin immunoreactivity in the nematode, Ascaris suum.

1. The leucokinins (LKs) are a group of eight related peptides isolated from the cockroach, Leucophaea maderae. 2. Antisera raised against LK-V, which were specific for the conserved mid to C-terminal region of the LKs, were used to immunostain the parasitic nematode Ascaris suum. 3. LK-IR was observed in neurons in the anterior nerve ring, retrovesicular ganglion, and ventral and dorsal nerve cords of the parasite. Immunostaining was specific in that it was abolished by preabsorption of the antiserum with different leucokinins. Some of the LK-immunoreactive neurons were identified on the basis of their morphological similarity with identified neurons in the free-living nematode Caenorhabditis elegans. 4. Immunoreactivity towards a number of other peptides, notably neuropeptide F, FMRF-amide, KGQELE and KELTAE, has previously been demonstrated in all LK-immunoreactive neurons, thus confirming the multiple-peptidergic nature of certain nematode nerves. 5. LK-IR was demonstrated and quantified in a number of tissues using RIA. Highest amounts were found in extracts of gut; LK-IR was also demonstrated in extracts of body wall, heads and tails, testes, ovaries and pseudocoelomic fluid. 6. The distribution of tissue LK-IR did not correlate with the amount of neuronal tissue in the samples. 7. Dilution experiments suggested that the LK-IR in the parasite is heterogeneous and that the peptide(s) in some tissues may not be analogous to the insect LKs. 8. The LK-IR in the parasite remains to be characterized; however, the results suggest that peptides related to the leucokinins may have a far wider phylogenetic distribution than has hitherto been thought.

Amino Acid Sequence↗
PubMed1993

Cytochemical observations on the nervous system of adult Corrigia vitta.

Adult Corrigia vitta (Trematoda: Dicrocoelidea) inhabit the pancreatic duct of the fieldmouse, Apodemus sylvaticus, where, in numbers, they may occlude the duct lumen and prevent the flow of pancreatic secretions. Enzyme histochemical and immunocytochemical techniques, in conjunction with confocal scanning laser microscopy, have been used to examine the localization and distribution of cholinergic, serotoninergic (5-HT, serotonin) and peptidergic components of the nervous system of the adult worm. All three classes of neuronal mediator showed a common pattern of staining, occurring throughout the central and peripheral nervous systems. Of the four peptide immunoreactivities (IR) demonstrated (pancreatic polypeptide (PP), peptide YY (PYY), substance P (SP), FMRFamide), PP-IR was the most predominant, occurring not only within the central ganglia and longitudinal nerve cords, but also in subtegumental plexuses and in fibres associated with the egg-forming apparatus. PYY and FMRFamide IRs were evident throughout the central and peripheral nervous systems; FMRFamide immunostaining, in particular, highlighted innervation of the ootype and immunoreactive cell bodies around the Mehlis' gland. Both SP- and 5-HT-IRs were restricted to the cerebral ganglia, ventral nerve cords and associated cell bodies. The distribution patterns of these peptides and 5-HT within the nervous system of C. vitta suggest they are likely to function as neuronal mediators. PP, PYY and FMRFamide may also serve in regulating egg production.

Animals↗
PubMed1993

The cholinergic, serotoninergic and peptidergic components of the nervous system of Moniezia expansa (Cestoda, Cyclophyllidea).

The central (CNS) and peripheral (PNS) nervous systems of the cyclophyllidean tapeworm, Moniezia expansa, were examined for the presence of cholinergic, serotoninergic and peptidergic elements using enzyme cytochemical and immunocytochemical techniques in conjunction with light and confocal scanning laser microscopy. Cholinesterase activity and 5-hydroxytryptamine- and regulatory peptide-immunoreactivities (IRs) were localized to the nerve fibres and cell bodies of all of the major neuronal components in the CNS of the worm, including the cerebral ganglia and connecting commissure, the 10 longitudinal nerve cords and associated transverse ring commissures. Although each of the 3 systems appeared well developed and comprised a significant portion of the nervous system, the serotoninergic constituent was the most highly developed, consisting of a vast array of nerve fibres and cell bodies distributed throughout the strobila of the worm. A close association of cholinesterase reactivity and peptide-IRs was evident throughout the CNS, indicating the possible co-localization of acetylcholine and neuropeptides. Within the PNS, cholinergic activity and serotoninergic- and peptidergic-IRs occurred in the subtegumental network of nerve fibres and somatic musculature. Although all 3 neurochemical elements were present in the acetabula, they were found in different nerve fibres; only cholinergic and peptidergic cell bodies were found. The common genital opening, vagina and ootype regions of the reproductive system displayed a rich innervation of all 3 types of neuronal populations. Within the peptidergic system, immunostaining with antisera raised to the C-terminus of the neuropeptide Y superfamily of peptides and the invertebrate peptides, neuropeptide F (M. expansa) and FMRFamide was the most prevalent. Limited positive-IR for substance P and neurokinin A were also recorded in the CNS of the worm.

Animals↗
PubMed1993

Immunocytochemical demonstration of neuropeptides in the central nervous system of the roundworm, Ascaris suum (Nematoda: Ascaroidea).

The localization and distribution of neuropeptides in the central nervous system of the pig roundworm, Ascaris suum, have been determined by an indirect immunofluorescence technique in conjunction with confocal microscopy. Antisera to 25 vertebrate peptides and two invertebrate peptides were used to screen the worm for immunoreactivity (IR). Immunostaining was obtained with antisera to pancreatic polypeptide (PP), peptide YY (PYY), neuropeptide Y (NPY), gastrin, cholecystokinin (CCK), substance P (SP), atrial natriuretic peptide (ANP), salmon gonadotropin-releasing hormone (SGnRH), mammalian gonadotropin-releasing hormone (MGnRH), chromogranin A (CGA) and FMRFamide. The most extensive patterns of IR occurred with antisera to PYY, FMRFamide and gastrin. IR was evident in nerve cells and fibres in the ganglia associated with the anterior nerve ring and in the main nerve cords and their commissures; IR to FMRFamide also occurred in the posterior nerve ring. Immunostaining for the other peptides was confined to the nerve cords, with the number of immunoreactive nerve fibres varying from peptide to peptide.

Animals↗
PubMed1993

The effect of different dietary fats on gastrin levels in the pyloric antrum and plasma of weaner and adult Wistar rats.

The effect of dietary fats on gastrin in the pyloric antrum and plasma of Wistar rats was examined. Two different age-groups of rats were fed on three different diets in which fat was in the form of menhaden oil (MO), hydrogenated coconut oil (CO) and safflower oil (SO) respectively. Control groups were fed on normal laboratory diet. Each diet was isoenergetic and no group showed significant differences in either food intake or weight gain during the experiment. Weaner rats fed on the MO diet exhibited significant reductions in both antral (P = 0.047) and plasma (P = 0.002) gastrin concentrations when compared with age-matched controls. Likewise, adult rats fed on the MO diet exhibited significant reductions in both antral (P = 0.008) and plasma (P = 0.002) gastrin concentrations. In addition, adult rats fed on the CO diet exhibited significant reductions in both antral (P = 0.047) and plasma gastrin (P = 0.002) concentrations. Rats from both age-groups fed on the SO diet exhibited no significant differences in gastrin concentrations when compared with their respective control groups. These findings indicate that the composition of dietary fat can have profound effects on both tissue and plasma concentrations of gastrin in rats.

Aging↗
PubMed1993

Appetite and appetite stimulants.

Poor appetite is a common symptom among cancer patients. It can lead to inadequate food intake, weight loss, physical debilitation and reduced tolerance to anti-neoplastic treatment. Although cancer-induced anorexia is not fully understood, there are some theories relating to its development. Interventions may be aimed at improving nutritional intake to prevent excessive weight loss when poor appetite exists, or it may concentrate on improving appetite by pharmacological means. Appetite should be considered alongside other aspects of symptom control and tackled aggressively when it is contributing to a poor quality of life.

Anorexia↗
PubMed1993

Effect of beta-adrenoceptor blockade on atrial natriuretic peptide levels during exercise in angina pectoris.

The effects of epanolol (200 mg once daily) and diltiazem (60 mg three times daily) on the response of atrial natriuretic peptide (ANP) to exercise were investigated in a double-blind placebo-controlled crossover study in 16 patients with angina pectoris. Exercise tolerance as assessed by peak oxygen consumption was similar with all treatments. Peak heart rate (mean and 95% confidence intervals) was lower (P < 0.05) with epanolol (121 (115-130) beats min-1) than with diltiazem (137 (126-148) beats min-1) or placebo (141 (130-152) beats min-1). ANP did not change from resting values with placebo or diltiazem, but rose significantly (P < 0.05) with epanolol from 19.7 (13.0-29.8) pg ml-1 (geometric mean and 95% confidence intervals) during supine rest to 49.6 (33.7-73.0) pg ml-1 at peak exercise. Since ANP release is stimulated by atrial distension, patients with untreated angina may stop exercise before atrial dilatation occurs. With beta-adrenoceptor blockade, a reduction in peak heart rate may necessitate increased chamber volumes to maintain cardiac output, accounting for the rise in ANP.

Adrenergic beta-Antagonists↗
PubMed1992

The primary structure of TE-6: a novel neuropeptide from the nematode Ascaris suum.

Extensive immunoreactivity (IR) towards a hexapeptide (sequence KGQELE), which flanks the C-terminus of the pancreastatin sequence in rat chromogranin A (CGA), is found throughout the nervous system of the nematode parasite Ascaris suum. The peptide IR was purified from the gonoduct of the parasite and found to have the sequence TKQELE. This peptide, designated TE-6, has some C-terminal homology with several regions of the CGA molecule. However, TE-6 was the only peptide isolated suggesting that either the nematode does not possess CGA, or that the -ELE regions of parasite CGA-like peptides which would be larger than TE-6 are not accessible to the antiserum in RIA, or are not being successfully extracted from the parasite. The N-terminus of TE-6 has little homology with any of the sequences preceding -ELE regions in CGA. This, and the fact that the tissue from which TE-6 was isolated does not contain IR towards another, highly conserved, region of the CGA molecule (WE-14) suggests that TE-6 may belong to a new class of regulatory peptide unrelated to CGA.

Amino Acid Sequence↗
PubMed1992

The primary structure of neuropeptide F (NPF) from the garden snail, Helix aspersa.

Neuropeptide F (NPF), originally isolated from the sheep tapeworm, Moniezia expansa, consists of 39 amino acid residues terminating in a phenylalaninamide. An analogous neuropeptide has been isolated and sequenced from extracts of circumoesophageal ganglia of the garden snail, Helix aspersa. This neuropeptide exhibits partial primary structural similarity to members of the vertebrate neuropeptide Y (NPY)/pancreatic polypeptide (PP) superfamily. NPF is thus of widespread occurrence in the nervous systems of invertebrates from different phyla and may represent the phylogenetic precursor of the vertebrate NPY/PP superfamily.

Amino Acid Sequence↗
PubMed1992

Cortical AMPA receptors: age-dependent regulation by cellular depolarization and agonist stimulation.

We have recently shown that a high-affinity AMPA receptor labelled with the antagonist [3H]CNQX can be regulated in a 'living' cortical slice preparation by agonist stimulation or changes in electrical activity (Lanius, R.A. and Shaw, C. (1992) Anat. Rec., in press). Based on a study of GABAA receptors (Shaw, C. and Scarth, B.A. (1992) Mol. Brain Res., in press), which showed age-dependent changes in regulation, we have now investigated the regulation of high-affinity AMPA receptors in neocortex at different stages in postnatal development. The results show that regulation by agonist stimulation and increases in bioelectric activity are age-dependent in amount and, in the latter case, in direction. Agonist stimulation using quisqualate resulted in a significant receptor down-regulation of approximately 7% at ages less than 20 days postnatal; in adult rats quisqualate led to a significant 23% decrease. Changes in bioelectric activity induced by a combination of veratridine and glutamate showed a significant increase in AMPA receptor number of 16% at ages less than 20 days, whereas such treatment resulted in a significant 18% decrease in adult rats. The present data reveal a near mirror-image to the effects of veratridine and glutamate and agonist on GABAA receptors in the same preparation, but with a temporal mismatch in the amount and direction of regulation. We speculate that the age-dependent differences in direction of regulation for the receptor populations which serve key excitatory and inhibitory functions in cortex may provide a molecular basis for the gradual decline of neuronal plasticity during the critical period.

Aging↗
PubMed1992

Peptide tyrosine phenylalanine: a novel neuropeptide F-related nonapeptide from the brain of the squid, Loligo vulgaris.

A novel nonapeptide, sequence YAIVARPRFamide, was isolated from brain extracts of the squid, L. vulgaris. Designated peptide tyrosine phenylalanine (PYF), the peptide shows marked homology with the C-terminal nonapeptides of pancreatic polypeptide and neuropeptide F (NPF) from a number of sources. If PYF is the C-terminal nonapeptide of squid NPF, then it may be derived by a novel processing mechanism involving specific cleavage between two TYR residues. PYF may be a highly truncated, receptor-active variant of NPF.

Amino Acid Sequence↗