The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Jacqueline Nelisis Zanoni - One of the best experts on this subject based on the ideXlab platform.
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does l glutamine supplemented diet extenuate no mediated damage on Myenteric Plexus of walker 256 tumor bearing rats
Food Research International, 2017Co-Authors: Geraldo Emilio Vicentini, Heber Amilcar Martins, Luciane Fracaro, Sara Raquel Garcia De Souza, Kassio P S Zanoni, Thamara Nishida Xavier Silva, Fernanda Paschoal Blegniski, Flavia Alessandra Guarnier, Jacqueline Nelisis ZanoniAbstract:Abstract This study was designed to appraise the relationship between enteric neuropathy and oxidative stress in cancer cachexia under l -glutamine-supplemented diet. Total and nitrergic neuronal populations were investigated in jejunum and ileum in four experimental groups: control (C); control l -glutamine-supplemented diet (CG); Walker-256 tumor (TW); and Walker-256 tumor supplemented with l -glutamine (TWG). In addition, local oxidative stress, neuronal nitric oxide synthase (nNOS) enzyme and nitric oxide (NO) levels were evaluated. Neuronal density and somatic area of the total and nitrergic populations were reduced in TW rats, which was accompanied by high oxidative stress, NO and nNOS levels. l -glutamine supplementation prevented neuronal atrophy, changes in pan neuronal density and nNOS overexpression (ileum), and restored total antioxidant capacity. Nevertheless, the oxidative stress was partially mitigated and no effect was observed on the reduction of nitrergic population and NO levels. l -glutamine-supplemented diet extenuates NO-mediated damage on the Myenteric Plexus although has a small benefit on oxidative stress.
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toxoplasma gondii causes death and plastic alteration in the jejunal Myenteric Plexus
World Journal of Gastroenterology, 2015Co-Authors: Eduardo Jose De Almeida Araujo, Larissa Marchi Zaniolo, Suellen Lais Vicentino, Marcelo Biondaro Gois, Jacqueline Nelisis Zanoni, Aristeu Vieira Da Silva, Debora De Mello Goncales SantanaAbstract:AIM: To assess the effects of ME-49 Toxoplasma gondii (T. gondii ) strain infection on the Myenteric Plexus and external muscle of the jejunum in rats.
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quantitative study of the Myenteric Plexus of the stomach of rats with streptozotocin induced diabetes
Arquivos De Neuro-psiquiatria, 2001Co-Authors: Cristina Elena Prado Teles Fregonesi, Marcilio Hubner De Mirandaneto, Sonia Lucy Molinari, Jacqueline Nelisis ZanoniAbstract:The purpose of the present study was to investigate the morphological and quantitative alterations of the Myenteric Plexus neurons of the stomach of rats with streptozotocin-induced chronic diabetes and compare them to those of non-diabetic animals. Samples from the body of the stomach were used for whole-mount preparations stained with NADH-diaphorase and for histological sections stained with hematoxylin-eosin. It was observed that diabetes cause a significant decrease on the number of neurons.
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morphological and quantitative analysis of the neurons of the Myenteric Plexus of the cecum of streptozotocin induced diabetic rats
Arquivos De Neuro-psiquiatria, 1997Co-Authors: Jacqueline Nelisis Zanoni, Marcilio Hubner De Mirandaneto, Roberto Barbosa Bazotte, Romeu Rodrigues De SouzaAbstract:The purpose of this work was to study the neurons of the Myenteric Plexus of the cecum of rats with chronic streptozotocin-induced diabetes. We used four experimental groups of animals. In groups D2 and D8 animals were killed two and eight months, respectively, after diabetes induction and groups C2 and C8 were used as controls. We carried out whole-mount preparations stanied with Giemsa and NADH-diaphorase. We verified that the diabetes did not alter the shape and disposition of the Myenteric ganglia; it provoked decrease on the neuronal density and increase on the incidence of weakly basophilic neurons. The effects of streptozotocin caused dilatation of the cecum still evidenced two months after induction, but no more observed on the eight months after induction. The smaller incidence of neurons in group D8 relative to group C8 was due to the early loss related to the drug toxicity and later to the aging in diabetic condition.
Geoffrey Burnstock - One of the best experts on this subject based on the ideXlab platform.
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development of nerves expressing p2x3 receptors in the Myenteric Plexus of rat stomach
Histochemistry and Cell Biology, 2004Co-Authors: Zhenghua Xiang, Geoffrey BurnstockAbstract:Development of neurones and fibres expressing P2X3 receptors in the Myenteric Plexus of rat stomach and coexistence of the P2X3 receptor with calbindin, calretinin and NOS during postnatal development, were investigated with immunostaining methods. Extrinsic nerves expressing P2X3 receptors appeared as early as E12 and were localised in the trunk and branches of the vagus nerve, which extended rapidly onto the whole rat stomach from E12 to E14. Intrinsic neurone cell bodies with P2X3-immunoreactivity in the Myenteric ganglia were first demonstrated postnatally at P1, and at P14, when the number of neurones expressing the P2X3 receptor peaked at 45%. P2X3 receptor-immunoreactivity decreased subsequently, and at P60 only about 11% were P2X3-immunoreactive. Intraganglionic laminar nerve endings and intramuscular arrays were first demonstrated postnatally at P1 and P7, respectively. In the early postnatal days, there were many growth cone-like structures with strong P2X3 immunostaining associated with these endings and arrays. Double-immunostaining showed that 9–15% of P2X3-immunoreactive neurones in the gastric Myenteric Plexus expressed calbindin D-28 k only in the early postnatal days, while 14–21% of neurones from P1 to P60 increasingly expressed calretinin. About 20% of neurones with P2X3 immunoreactivity coexpressed NOS throughout perinatal development.
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a new method for the isolation of Myenteric Plexus from the newborn rat gastrointestinal tract
Brain Research Protocols, 1997Co-Authors: Karlherbert Schafer, Geoffrey Burnstock, Jill M Saffrey, Pedro MestresventuraAbstract:The Myenteric Plexus is not only essential for gastrointestinal functions, but it is also a very interesting model for the study of neuronal circuits and neuron-glial interrelationships and may be a valuable source of donor tissue, for grafting into different regions of the central nervous system. For both grafting and culture procedures it is a great advantage to obtain the maximum amount of tissue. To date, most studies have isolated the Myenteric Plexus by manual microdissection after collagenase digestion. Using this method, it has only been possible to obtain relatively small amounts of the Myenteric Plexus, mostly from the cecum and proximal colon of the guinea-pig or rat. We present here a new method, which enables much greater quantities of the Plexus from the small intestine and colon to be obtained. The Myenteric Plexus of the entire small intestine can be isolated by a combination of enzymatic digestion and mechanical agitation. The method works from birth up to 3 week old pups, and with some modifications tissue from older or even adult animals can also be processed. Another advantage over the microdissection method is that the Myenteric Plexuses of the different parts of the intestine can be cultured and studied separately.
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tyrosine hydroxylase containing fibres extend from the rat corpus striatum into grafts of muscularis externa and Myenteric Plexus
Neuroscience Letters, 1995Co-Authors: Elizabeth M.m. Tew, Alison Fearon, P N Anderson, Geoffrey BurnstockAbstract:Intrastriatal grafts of Myenteric Plexus produce a vigorous sprouting response in the surrounding rat brain. Since the striatum receives profuse dopaminergic innervation from the substantia nigra, we have investigated whether central catecholaminergic neurons participated in the sprouting response and grew into grafts of adult Myenteric Plexus (surrounded by smooth muscle) implanted in the adult corpus striatum. Three weeks after implantation, tyrosine hydroxylase-containing fibres were observed to have grown into, and ramified within, the grafts. The extent of innervation was increased 6 weeks after implantation, and was not diminished if the superior cervical ganglia were removed (to destroy any fibres of sympathetic origin).
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colocalization of nitric oxide synthase and nadph diaphorase in the Myenteric Plexus of the rat gut
Neuroscience Letters, 1992Co-Authors: A Belai, Harald H H W Schmidt, C H V Hoyle, C J S Hassall, M J Saffrey, J Moss, U Forstermann, F Murad, Geoffrey BurnstockAbstract:The pattern of distribution and colocalization of nitric oxide-synthase (NOS) and NADPH-diaphorase in the Myenteric Plexus of whole-mount preparations of the antrum, duodenum, ileum, caecum, proximal colon and distal colon of the rat were investigated using immunohistochemical and histochemical staining techniques. Almost all the Myenteric neurons that were NOS-positive in all regions of the gut examined were also stained for NADPH-diaphorase. However, in the stomach, duodenum and ileum, only a few of the NOS-positive nerve fibres in the tertiary and secondary Plexuses and circular muscle layer were also stained for NADPH-diaphorase, whereas in the caecum and distal colon almost all the NOS-positive nerve fibres were also stained for NADPH-diaphorase. The results in the present study are consistent with the view that nitric oxide (NO) has a mediating role in gastrointestinal neurotransmission.
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IMPLANTATION OF THE Myenteric Plexus INTO THE CORPUS STRIATUM OF ADULT-RATS - SURVIVAL OF THE NEURONS AND GLIA AND INTERACTIONS WITH HOST BRAIN
Restorative Neurology and Neuroscience, 1992Co-Authors: Elizabeth M.m. Tew, Patrick N. Anderson, Geoffrey BurnstockAbstract:Live or freeze-killed syngeneic adult muscularis externa, comprising Myenteric Plexus sandwiched between two layers of smooth muscle, was implanted into the corpus striatum of adult Fischer rats and examined electron microscopically 10 days to 6 weeks after operation. Living grafts contained healthy neurons and glial cells at all time-periods examined, although some areas of necrosis were observed. After 10 days, the glia limitans around the grafts were poorly developed and the adjacent brain tissue contained only a small number of small non-myelinated axons. After 3 and 6 weeks, the brain surrounding the living grafts contained many clusters of small non-myelinated axons. Bundles of putative central nervous system (CNS) axonal sprouts had invaded the grafts, making contact with enteric glia, despite the presence of a well-developed glia limitans at the interface with the brain. In the longer-term grafts some CNS axonal sprouts in the Myenteric Plexus enlarged and became myelinated. A few astrocyte processes but no axons were found in the freeze-kilied grafts. The brain surrounding the freeze-killed grafts appeared to contain fewer axonal sprouts than were present around the living grafts. The possibility that the living grafts may promote both the sprouting and the elongation of CNS axons is discussed.
Chung Owyang - One of the best experts on this subject based on the ideXlab platform.
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upregulation of bile acid receptor tgr5 and nnos in gastric Myenteric Plexus is responsible for delayed gastric emptying after chronic high fat feeding in rats
American Journal of Physiology-gastrointestinal and Liver Physiology, 2015Co-Authors: Hui Zhou, Shiyi Zhou, Jun Gao, Guanpo Zhang, Chung OwyangAbstract:Chronic high-fat feeding is associated with functional dyspepsia and delayed gastric emptying. We hypothesize that high-fat feeding upregulates gastric neuronal nitric oxide synthase (nNOS) expression, resulting in delayed gastric emptying. We propose this is mediated by increased bile acid action on bile acid receptor 1 (TGR5) located on nNOS gastric neurons. To test this hypothesis, rats were fed regular chow or a high-fat diet for 2 wk. Rats fed the high-fat diet were subjected to concurrent feeding with oral cholestyramine or terminal ileum resection. TGR5 and nNOS expression in gastric tissue was measured by immunohistochemistry, PCR, and Western blot. Gastric motility was assessed by organ bath and solid-phase gastric emptying studies. The 2-wk high-fat diet caused a significant increase in neurons coexpressing nNOS and TGR5 in the gastric Myenteric Plexus and an increase in nNOS and TGR5 gene expression, 67 and 111%, respectively. Enhanced nonadrenergic, noncholinergic (NANC) relaxation, deoxycholic acid (DCA)-induced inhibition in fundic tissue, and a 26% delay in gastric emptying accompanied these changes. A 24-h incubation of whole-mount gastric fundus with DCA resulted in increased nNOS and TGR5 protein expression, 41 and 37%, respectively. Oral cholestyramine and terminal ileum resection restored the enhanced gastric relaxation, as well as the elevated nNOS and TGR5 expression evoked by high-fat feeding. Cholestyramine also prevented the delay in gastric emptying. We conclude that increased levels of circulatory bile acids induced by high-fat feeding upregulate nNOS and TGR5 expression in the gastric Myenteric Plexus, resulting in enhanced NANC relaxation and delayed gastric emptying.
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decreased expression of nitric oxide synthase in the colonic Myenteric Plexus of aged rats
Brain Research, 2000Co-Authors: Toku Takahashi, Chung Owyang, Ammar Qoubaitary, John W WileyAbstract:Nitric oxide (NO) is a major non-adrenergic, non-cholinergic (NANC) inhibitory neurotransmitter in the gastrointestinal tract. NO released from the Myenteric Plexus enhances colonic transit and facilitates propulsion of the colonic contents by mediating descending relaxation. Although it has been suggested that colonic transit delays with aging, the mechanism of delayed colonic transit in aging remains unclear. We hypothesized that advanced age is associated with decreased expression of neuronal NO synthase (nNOS) and concomitant reduction in synthesis of NO in the rat colon. We studied nNOS mRNA expression, nNOS-immunohistochemistry, nNOS-immunoblotting and NOS catalytic activity in the mid-colon obtained from young (age 4-8 months) and aged (age 22-28 months) Fisher (F344xBN)F1 rats. Western blot analysis of PGP 9.5, a generic neuronal marker, of the colonic tissues were employed to study whether the total number of neurons of the Myenteric Plexus is reduced with aging. The number of nNOS-immunoreactive cells and nNOS synthesis in the colonic Myenteric Plexus were significantly reduced in aged rats. In contrast, expression of PGP 9.5 in colonic tissues was not affected in aged rats. Northern blot analysis demonstrated that the expression of neuronal nNOS mRNA was significantly reduced in the colonic tissues in aged rats. Basal and veratridine-induced release of L-[(3)H]citrulline were significantly decreased in colonic tissues from aged rats, compared to young rats. It is suggested that advanced age is associated with diminished gene expression of nNOS, nNOS synthesis and catalytic activity of NOS. This may explain the mechanism of delayed colonic transit observed in advanced age.
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nicotinic receptor mediates nitric oxide synthase expression in the rat gastric Myenteric Plexus
Journal of Clinical Investigation, 1998Co-Authors: K Nakamura, Tomoyuki Takahashi, M Taniuchi, Chun Xiao Hsu, Chung OwyangAbstract:The mechanism that regulates the synthesis of nitric oxide synthase (NOS), a key enzyme responsible for NO production in the Myenteric Plexus, remains unknown. We investigated the roles of the vagal nerve and nicotinic synapses in the mediation of NOS synthesis in the gastric Myenteric Plexus in rats. Truncal vagotomy and administration of hexamethonium significantly reduced nonadrenergic, noncholinergic relaxation, the catalytic activity of NOS, the number of NOS-immunoreactive cells, and the density of NOS-immunoreactive bands and NOS mRNA bands obtained from gastric tissue. These results suggest that NOS expression in the gastric Myenteric Plexus is controlled by the vagal nerve and nicotinic synapses. We also investigated if stimulation of the nicotinic receptor increases neuronal NOS (nNOS) expression in cultured gastric Myenteric ganglia. Incubation of cultured gastric Myenteric ganglia with the nicotinic receptor agonist, 1,1-dimethyl-4-phenylpiperizinium (DMPP, 10(-10)-10(-7) M), for 24 h significantly increased the number of nNOS-immunoreactive cells and the density of immunoreactive nNOS bands and nNOS mRNA bands. nNOS mRNA expression stimulated by DMPP was antagonized by a protein kinase C antagonist, a phospholipase C inhibitor, and an intracellular Ca2+ chelator. We concluded that activation of the nicotinic receptor stimulates a Ca2+-dependent protein kinase C pathway, which in turn, upregulates nNOS mRNA expression and nNOS synthesis in the gastric Myenteric Plexus.
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extrinsic neural control of nitric oxide synthase expression in the Myenteric Plexus of rat jejunum
The Journal of Physiology, 1998Co-Authors: Toku Takahashi, Koji Nakao, Joji Utsunomiya, Chung OwyangAbstract:Small bowel transplantation is a life-saving option for patients who suffer from chronic intestinal failure (Todo, Reyes, Furukawa, Abu-Elmagd, Lee & Tzakis, 1995). However, abnormal motility of the transplanted small bowel can lead to various complications such as malabsorption and diarrhoea (Todo et al. 1995). Extrinsic and intrinsic nerves regulate the motility of the small intestine (Andrews, Grundy & Lawes, 1980) and transplantation causes complete disruption of the extrinsic innervation to the graft. The denervation may damage the neuronal function in the Myenteric Plexus of the grafted small intestine. The abnormal release of excitatory and inhibitory neurotransmitters in the denervated bowel may alter the motility pattern. It has been demonstrated that the increase in intestinal contractile motility after transplantation is associated with a marked increase of excitatory non-adrenergic, non-cholinergic (NANC) neurotransmitter (probably substance P) (Ishii, Kusunoki, Fujita, Yamamura & Utsunomiya, 1994; Kusunoki, Ishii, Nakao, Fujiwara, Yamamura & Utsunomiya, 1995). Nitric oxide (NO) is an important inhibitory NANC neurotransmitter in the gastrointestinal tract, including the small intestine. NO released in response to stimulation of the Myenteric Plexus causes relaxation of the smooth muscle in the gastrointestinal tract (Bredt, Hwang & Snyder, 1990; Bult, Boeckxstaens, Pelckmans, Jordaens, Van Maercke & Herman, 1990; Boeckxstaens, Pelckmans, Bogers, Bult, De Man & Oosterbosch, 1991; D'Amato, Curro & Montuschi, 1992; Takahashi & Owyang, 1995). The rapid relaxation induced by NANC stimulation is significantly antagonized by the NO biosynthesis inhibitors, NG-nitro-L-arginine (L-NNA) and NG-nitro-L-arginine methyl ester (L-NAME), in the small intestine (Boeckxstaens, Pelckmans, Bult, De Man, Herman & Van Maercke, 1990; Bult et al. 1990). In addition, NO synthase (NOS) has been detected in the Myenteric Plexus (Bredt et al. 1990; Aimi, Kimura, Kinoshita, Minami, Fujimura & Vincent, 1993) and in the central nervous system (Bredt et al. 1990). These observations suggest that NO neurons in the Myenteric Plexus play an important role in mediating intestinal relaxation. We have recently shown that the L-NAME-sensitive NANC relaxation was significantly enhanced in the grafted small intestine, suggesting an enhanced functioning of the NO pathway in the Myenteric Plexus (Nakao, Ishii, Kusunoki, Yamamura & Utsunomiya, 1997). It is conceivable that the increased activity of the NO pathway is, in part, caused by extrinsic denervation following transplantation. The physiological role of extrinsic innervation on NO neurons in the Myenteric Plexus of the small intestine remains unknown. We have shown that the expression of NOS, a key enzyme responsible for the release of NO, in the Myenteric Plexus is controlled by the vagus nerve in the rat stomach (Nakamura, Takahashi, Campbell, Taniuchi & Owyang, 1996). However, it is not known if the extrinsic vagus nerve and splanchnic nerve regulate NOS expression in the Myenteric Plexus of the small intestine. In this study, we investigated the effect of extrinsic denervation on NOS expression in rat jejunum. We demonstrate that splanchnic denervation causes enhanced NOS mRNA expression and NOS synthesis in the jejunal Myenteric Plexus, resulting in enhanced NANC relaxation of the jejunum. This goes some way towards explaining the abnormal motility that occurs after transplantation of the small bowel.
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impaired expression of nitric oxide synthase in the gastric Myenteric Plexus of spontaneously diabetic rats
Gastroenterology, 1997Co-Authors: Toku Takahashi, K Nakamura, Hiroshi Itoh, Anders A F Sima, Chung OwyangAbstract:Abstract BACKGROUND & AIMS: The mechanism responsible for defective gastric accommodation in diabetes is unknown. The aim of this study was to investigate if this abnormality is due to a defective nitric oxide pathway secondary to impaired nitric oxide synthase (NOS) expression in the gastric Myenteric Plexus. METHODS: To test this hypothesis, we studied nonadrenergic, noncholinergic (NANC) relaxation, NOS activity, NADPH diaphorase histochemistry, NOS immunohistochemistry, NOS immunoblotting, and NOS messenger RNA expression in the gastric Myenteric Plexus of spontaneously diabetic biobreeding/Worcester (BB/W) rats. Age-matched nondiabetic Wistar rats were used as controls. RESULTS: Gastric neuromuscular preparations from control rats showed a frequency-dependent NANC relaxation in response to transmural stimulation. This relaxation was markedly antagonized by N(G)-nitro-L- arginine-methyl ester, indicating mediation by the neuronal release of NO. The NANC relaxation in gastric muscle preparations obtained from diabetic BB/W rats was significantly impaired. The number of NOS- immunoreactive cells in the gastric Myenteric Plexus and the NOS activity were significantly reduced in diabetic BB/W rats, suggesting that NOS synthesis is impaired in diabetes. Northern blot analysis showed that the density of NOS messenger RNA bands at 9.5 kilobases was significantly reduced in the gastric tissues of diabetic BB/W rats. CONCLUSIONS: These results indicate that gastric relaxation in diabetics is hampered mainly by impaired NOS expression in the gastric Myenteric Plexus. (Gastroenterology 1997 Nov;113(5):1535-44)
F Derrico - One of the best experts on this subject based on the ideXlab platform.
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estrogen receptor β controls proliferation of enteric glia and differentiation of neurons in the Myenteric Plexus after damage
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: F Derrico, Gera Goverse, Yubing Dai, Michelle Stakenborg, Evelien Labeeuw, V De Simone, Bram Verstockt, Pedro J GomezpinillaAbstract:Injury to the enteric nervous system (ENS) can cause several gastrointestinal (GI) disorders including achalasia, irritable bowel syndrome, and gastroparesis. Recently, a subpopulation of enteric glial cells with neuronal stem/progenitor properties (ENSCs) has been identified in the adult ENS. ENSCs have the ability of reconstituting the enteric neuronal pool after damage of the Myenteric Plexus. Since the estrogen receptor β (ERβ) is expressed in enteric glial cells and neurons, we investigated whether a selective ERβ agonist, LY3201, can influence neuronal and glial cell differentiation. Myenteric ganglia from the murine muscularis externa were isolated and cultured in either glial cell medium or neuronal medium. In glial cell medium, the number of glial progenitor cells (Sox10+) was increased by fourfold in the presence of LY3201. In the neuronal medium supplemented with an antimitotic agent to block glial cell proliferation, LY3201 elicited a 2.7-fold increase in the number of neurons (neurofilament+ or HuC/D+). In addition, the effect of LY3201 was evaluated in vivo in two murine models of enteric neuronal damage and loss, namely, high-fat diet and topical application of the cationic detergent benzalkonium chloride (BAC) on the intestinal serosa, respectively. In both models, treatment with LY3201 significantly increased the recovery of neurons after damage. Thus, LY3201 was able to stimulate glial-to-neuron cell differentiation in vitro and promoted neurogenesis in the damaged Myenteric Plexus in vivo. Overall, our study suggests that selective ERβ agonists may represent a therapeutic tool to treat patients suffering from GI disorders, caused by excessive neuronal/glial cell damage.
Terry L Powley - One of the best experts on this subject based on the ideXlab platform.
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alpha synuclein immunopositive aggregates in the Myenteric Plexus of the aging fischer 344 rat
Experimental Neurology, 2009Co-Authors: Robert J Phillips, Gary C Walter, Brittany E Ringer, Katherine M Higgs, Terry L PowleyAbstract:Dystrophic axons and terminals are common in the Myenteric Plexus and smooth muscle of the gastrointestinal (GI) tract of aged rats. In young adult rats, alpha-synuclein in its normal state is abundant throughout the Myenteric Plexus, making this protein-which is prone to fibrillization-a candidate marker for axonopathies in the aged rat. To determine if aggregation of alpha-synuclein is involved in the formation of age-related enteric neuropathies, we sampled the stomach, small intestine and large intestine of adult, middle-aged, and aged virgin male Fischer 344 rats stained for alpha-synuclein in both its normal and pathological states. Alpha-synuclein-positive dystrophic axons and terminals were present throughout the GI tract of middle-aged and aged rats, with immunohistochemical double labeling demonstrating co-localization within nitric oxide synthase-, calretinin-, calbindin-, or tyrosine hydroxylase-positive markedly swollen neurites. However, other dystrophic neurites positive for each of these four markers were not co-reactive for alpha-synuclein. Similarly, a subpopulation of alpha-synuclein inclusions contained deposits immunostained with an anti-tau phospho-specific Ser(262) antibody, but not all of these hyperphosphorylated tau-positive aggregates were co-localized with alpha-synuclein. The presence of heteroplastic and potentially degenerating neural elements and protein aggregates both positive and negative for alpha-synuclein suggests a complex chronological relationship between the onset of degenerative changes and the accumulation of misfolded proteins. Additionally, proteins other than alpha-synuclein appear to be involved in age-related axonopathies. Finally, this study establishes the utility of the aging Fischer 344 rat for the study of synucleopathies and tauopathies in the GI tract.
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Effects of age on sympathetic innervation of the Myenteric Plexus and gastrointestinal smooth muscle of Fischer 344 rats
Anatomy and embryology, 2006Co-Authors: Robert J Phillips, Brie S Rhodes, Terry L PowleyAbstract:Loss of Myenteric neurons with age is well documented, however little is known about age-related changes of the sympathetic innervation of the Myenteric Plexus and gastrointestinal smooth muscle. The goal of the present study, therefore, was to evaluate the influence of age on the sympathetic innervation of the Myenteric Plexus throughout the gastrointestinal tract. Ad libitum fed virgin male Fischer 344 rats at 3, 15-16, 24, and 27-28 months of age were sampled. Whole mounts of the stomach, small intestine, and large intestine were processed with an antibody to tyrosine hydroxylase (TH). Additionally, some specimens labeled for TH were stained for NADPH-diaphorase to selectively label the nitrergic subpopulation of neurons in the Myenteric Plexus. Age-related changes in the TH-positive axons occurred as early as 15-16 months and became more pronounced by 27-28 months. Changes included markedly swollen axons and terminals and a decrease in the intensity of TH staining in some of the surviving processes. Similarly, swollen NADPH-diaphorase-positive axons were found in the Myenteric ganglia and secondary Plexus between ganglia in the whole mounts of rats 15-28 months of age, but swollen nitrergic axons and dystrophic TH-positive axons were never present in the same ganglion or connective. Therefore, in the aged rat, deterioration of the sympathetic innervation of the Myenteric Plexus could be one possible mechanism for the age-related decline in gastrointestinal motor function evidenced in the elderly.
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Quantification of neurons in the Myenteric Plexus: an evaluation of putative pan-neuronal markers.
Journal of neuroscience methods, 2004Co-Authors: Robert J Phillips, Brie S Rhodes, David A Zopf, Sylvia L Hargrave, Terry L PowleyAbstract:Accurate estimates of the total number of neurons located in the wall of the gut are essential for studies of the enteric nervous system (ENS). Though several stains and antibodies are used routinely as pan-neuronal markers, controversies of relative sensitivity and completeness have been difficult to resolve, at least in part because comparisons often must be made across experiments and laboratories. Therefore, we evaluated the efficacy of four putative pan-neuronal markers for the ENS, under comparable conditions. Neurons in the Myenteric Plexus of wholemounts taken from the small intestines of Fischer 344 rats were stained using Cuprolinic Blue, anti-HuC/D, anti-protein gene product 9.5, or FluoroGold injections followed by permanent labeling with an antibody to the FluoroGold molecule. All four markers had useful features, but both protein gene product 9.5 and FluoroGold were found to be problematic for obtaining reliable counts. As a result, only neurons labeled with either Cuprolinic Blue or anti-HuC/D were compared quantitatively. Based on counts from permanently labeled tissue, Cuprolinic Blue and HuC/D were similarly effective in labeling all neurons. Because the two protocols have different strengths and weaknesses, Cuprolinic Blue and HuC/D provide a complementary set of labels to study the total neuronal population of the ENS.
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aging of the Myenteric Plexus neuronal loss is specific to cholinergic neurons
Autonomic Neuroscience: Basic and Clinical, 2003Co-Authors: Robert J Phillips, Elizabeth J Kieffer, Terry L PowleyAbstract:Neuron loss occurs in the Myenteric Plexus of the aged rat. The Myenteric Plexus is composed of two mutually exclusive neuronal subpopulations expressing, respectively, nitrergic and cholinergic phenotypes. The goal of the present study, therefore, was to determine if neuron loss is specific to one phenotype, or occurs in both. Ad libitum fed virgin male Fischer 344 rats of 3 and 24 months of age were used in each of two neuronal staining protocols (n=10/age/neuron stain). The stomach, duodenum, jejunum, ileum, colon, and rectum were prepared as whole mounts and processed with either NADPHd or Cuprolinic Blue to stain, respectively, the nitrergic subpopulation or the entire population of Myenteric neurons. Neuron numbers and sizes were determined for each preparation. Neuron counts from 24-month-old rats were corrected for changes in tissue area resulting from growth. There was no age-related loss of NADPHd-positive neurons for any of the regions sampled, whereas significant losses of Cuprolinic Blue-labeled neurons occurred in the small and large intestines of 24-month-old rats. At the two ages, the average neuron sizes were similar in the stomach and small intestine for both stains, but neurons in the large intestine were significantly larger at 24 months. In addition, numerous swollen NADPHd-positive axons were found in the large intestine at 24 months. These findings support the hypothesis that age-related cell loss in the small and large intestines occurs exclusively in the cholinergic subpopulation. It appears, however, from the somatic hypertrophy and the presence of swollen axons that the nitrergic neurons are not completely spared from the effects of age.
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nitric oxide synthase containing neurons in the Myenteric Plexus of the rat gastrointestinal tract distribution and regional density
Anatomy and Embryology, 1999Co-Authors: Michael K Jarvinen, Wyatt J Wollmann, Teresa A Powrozek, Jonathan A Schultz, Terry L PowleyAbstract:Nitrergic (NO) neurons play crucial inhibitory roles in the control of gut motility. Variations in the density of these neurons within the gastrointestinal tract (GI) may provide useful functional information, but, most surveys available have employed limited and/or highly localized samples. It remains unclear to what extent (a) NO neurons are concentrated disproportionately in particular GI regions, or (b) variations in NO cell number merely reflect changes in overall Myenteric neuron density. This experiment surveyed the distributions of neuronal nitric oxide synthase-positive (NOS+) and other Myenteric neurons in the GI tract, using immunohistochemical and Cuprolinic blue counterstaining techniques. Adjustable sampling grids superimposed on wholemounts were used to investigate the topographic patterns in the stomach (90 sampling sites; 45 per side) and proximal duodenum (63 loci). We present four major findings: First, variations were detected in the number of NOS+ neurons in specific regions of the stomach (e.g., corpus > antrum approximately equal to forestomach) and along both longitudinal (oral > anal) and circumferential (mesenteric > antimesenteric) axes in the duodenum. Second, the variations in NOS+ neuronal counts within each organ covaried with the total number of Myenteric neurons at different locations (stomach, r=0.77; duodenum, r=0.59), suggesting that local Myenteric Plexus density is a factor determining NOS+ cell concentrations. Third, in contrast to such a principle of covariation within each organ, NOS+ neurons constituted a consistently smaller proportion of gastric (20%) than of duodenal (28%) Myenteric Plexus neurons, suggesting that a second principle controls the characteristic percentages of the Myenteric Plexus that express NOS in different organs. Fourth, the regional samples were used to extrapolate the overall number of NOS+ and total Myenteric cells in the rat stomach (43,000; 217,000) and first 3.5 cm of the small intestine (29,000; 103,000). These results, taken together, also suggest that the surveying protocol used is capable of detecting subtle differences in cellular distributions, thus providing a practical strategy for investigating patterns of chemical phenotypes within the GI tract.
