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At least 379 records · Page 21Linked to original sources
PubMed2000

Receptors for NPY in peripheral tissues bioassays.

Neuropeptide Y (NPY) and its congeners, peptide YY (PYY) and the pancreatic polypeptide (PP), have a large spectrum of peripheral actions. NPY is found in peripheral neurons, co-localized or not with noradrenaline; PYY and PP are expressed in endocrine cells of the pancreas and in the intestine of vertebrates. NPY is the most abundant peptide in the brain and is involved in the regulation of food intake and of circadian rhythm. It intervenes also in the process of anxiety and memory. NPY is a potent vasoconstrictor, a cardiac stimulant, and may affect the gut through enteric neurons. PYY and PP act mainly on the gastrointestinal system; however, when in blood, they can cross-react with functional sites elsewhere and replace NPY in some parts of the brain (e.g. regions involved in feeding behavior). These peptides act through G protein coupled receptors (GPCR) of which five different types are known and have been cloned (1,2); functional sites (receptors) for NPY have been found in vessels, the gut, and in vasa deferentia (3-6).

Animals↗
PubMed2003

Effect of obesity on susceptibility to fatty acid-induced peripheral tissue insulin resistance.

Elevation of plasma nonesterified fatty acid (NEFA) levels has been shown to impair the actions of insulin on peripheral glucose uptake and suppression of hepatic glucose output (HGO). These studies have been conducted almost exclusively in healthy, lean men. We therefore set out to test the hypothesis that obese subjects, because they are already insulin-resistant, are less susceptible than lean subjects to the inhibitory effects of elevated NEFA on insulin-stimulated glucose disposal. We studied 15 lean (11 men, 4 women; age, 45 +/- 3 years [mean +/- SE]; body mass index [BMI], 22.7 +/- 0.6 kg/m(2)) and 15 obese normal subjects (11 men, 4 women; 49 +/- 3 years; 31.7 +/- 1.0 kg/m(2)). Each subject underwent two 5-hour 80-mU/m(2)/min hyperinsulinemic euglycemic clamps with measurement of glucose kinetics (intravenous 3-(3)H-glucose). Plasma NEFA levels were elevated in one study for 3 hours before and during the clamp ( approximately 1 mmol/L in both groups) by infusion of 20% Intralipid (60 mL/h) and heparin (900 U/h). The obese subjects had higher fasting insulin levels (9.1 +/- 1.1 v 4.8 +/- 0.6 mU/L, P <.005) and were insulin-resistant (glucose disposal rate [GDR] at the end of the control glucose clamps: obese, 7.96 +/- 0.55, lean, 10.24 +/- 0.35 mg/kg/min, P <.002). Contrary to our hypothesis, elevation of plasma NEFA had a similar effect in the lean and obese subjects, both in terms of the absolute reduction of insulin stimulated GDR in the lean (1.82 +/- 0.36 mg/kg/min decrement) and obese subjects (2.03 +/- 0.37 mg/kg/min decrement) and the overall percentage reduction in GDR (lean, 17.1% +/- 3.1%; obese, 24.5% +/- 4.2%; difference not significant [NS]). Suppression of HGO during the lipid clamps was also impaired to a similar extent in the 2 groups. Findings were similar for the 9 obese subjects with a BMI of 30 kg/m(2) or more. Combining the 2 groups, the NEFA induced reduction of insulin stimulated GDR did not correlate with BMI (r = 0.08, NS) or with insulin sensitivity (GDR) measured in the control study (r = 0.11, NS). In summary, the effect of a short term elevation of plasma NEFA levels on insulin stimulated GDR and suppression of HGO is comparable in lean and moderately obese subjects.

Blood Glucose↗
PubMed1989

Oxygen delivery and uptake by peripheral tissues: physiology and pathophysiology.

When oxygen availability to tissues becomes limited, several mechanisms interact to maintain a supply-independent O2 uptake by tissues. Among tissues, adrenergic vasoconstriction prevents a vascular steal of a limited O2 supply by tissues with low metabolic demands. Within tissues, increases in perfused capillary density facilitate an increase in the extraction ratio for oxygen ([CaO2-CvO2]/CaO2). Factors that disrupt the physiologic balance between sympathetic-mediated vasoconstriction and local metabolic vasodilation may impair the ability of the organism to adjust the regional extraction of oxygen in response to changes in O2 delivery, resulting in a pathologic dependence of O2 uptake on supply. Patients with ARDS have demonstrated such an O2 extraction defect, although the mechanism is not fully understood. Although a tissue mitochondrial abnormality could explain these findings, experimental studies of endotoxemia and bacteremia demonstrate a peripheral O2 extraction defect similar to that seen in patients. This defect has been found at the whole body level and within intestine, but not within skeletal muscle. Evidence points to a defect in microvascular control as the mechanism responsible for the defect. Other evidence suggests that damaged peripheral endothelial cells may mediate the loss of vascular control. Hence, in patients with ARDS a damaged endothelium in the pulmonary circulation contributes to the lung edemagenesis, and damaged peripheral endothelium may mediate the defect in microvascular control, leading to the pathologic dependence of oxygen uptake on delivery.

Endothelium↗
PubMed2006

Endogenous cannabinoids in the brain and peripheral tissues: regulation of their levels and control of food intake.

Endocannabinoids were first defined in 1995 as 'endogenous substances capable of binding to and functionally activating the cannabinoid receptors'. To date, two well-established endocannabinoids, N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), as well as a few other putative ligands, all derived from long-chain polyunsaturated fatty acids, have been identified in animal tissues. The biosynthetic and metabolic pathways for anandamide and 2-AG have been elucidated, and most of the enzymes therein involved have been cloned. We now know that CB1 receptors, and endocannabinoids in tissue concentrations sufficient to activate them, are more widely distributed than originally thought, and are found in brain and peripheral organs involved in the control of energy intake and processing, including the hypothalamus, nucleus accumbens, brainstem, vagus nerve, gastrointestinal tract, adipose tissue and liver. Endocannabinoid biosynthetic and inactivating pathways are under the regulation of neuropeptides and hormones involved in energy homeostasis, and endocannabinoid levels are directly affected by the diet. Endocannabinoids, in turn, regulate the expression and action of mediators involved in nutrient intake and processing. These cross-talks are at the basis of the proposed role of endocannabinoid signalling in the control of food intake, from invertebrates to lower vertebrates and mammals, and their perturbation appears to contribute to the development of eating disorders.

Appetite Regulation↗
PubMed1998

Changes in expression and localization of hemopexin and its transcripts in injured nervous system: a comparison of central and peripheral tissues.

The recent demonstration of hemopexin synthesis in the adult rat sciatic nerve and its accumulation after injury has raised the question of the possible role of this acute phase protein during the process of nerve repair. To gain insight into its function, we have compared the distribution of both hemopexin and its messenger RNA in the peripheral and the central nervous systems. We find that hemopexin is present in all types of peripheral nerves and ganglia, confined to the extracellular matrix and basement membranes of the endoneurium, blood vessels and connective tissues. After injury, hemopexin messenger RNA is overexpressed by Schwann cells, fibroblasts and invading macrophages. The content in hemopexin protein increases in all nerves studied, without changes in localization. Therefore, hemopexin does not appear to be associated with the fate of myelin or with the regeneration of a particular type of nerve fibre. In the central nervous system, hemopexin messenger RNA cannot be detected and the protein is only found in basement membranes of the vascular system (capillaries, meninges and choroid plexus). Furthermore, hemopexin and its messenger RNA remain absent from the distal part of the injured optic nerves. Our results further support the idea that hemopexin plays specific roles during nerve repair, and that it may be associated with the endoneurial extracellular matrix.

Animals↗
PubMed1988

Comparison of inflammatory cells in bronchoalveolar fluid with those in the lumen and tissue peripheral airways and alveolar airspace.

This study compares the inflammatory cell types in the alveolar airspace, peripheral airways, and bronchoalveolar lavage fluid of 65 human lung specimens removed surgically. The data show that the cellular population in the airway tissue is composed of approximately 2-4% neutrophils, and 96-98% mononuclear inflammatory cells. This contrasts with the airway lumen, which contains approximately 5-14% neutrophils, while the alveolar airspace contains 3%, and the lavage fluid contains 4% neutrophils. There is a significant correlation between the percentage of PMN in the walls of the membranous and respiratory bronchioles, as well as between the walls and lumens of respiratory and membranous bronchioles. We conclude that: 1. The lumen of the membranous bronchioles contains a greater percentage of PMN than the lumen of the respiratory bronchiole or of the alveoli. 2. Neutrophils are present in the alveolar airspace. 3. The percentages of PMN present in the lumen of the respiratory bronchiole, alveoli, and lavage fluid are similar. 4. The correlation between percentage of PMN in airway wall and lumen suggests a cellular equilibrium between the 2 sites. 5. In this groups of lungs, there is an apparent stereotypic inflammatory response in that the percentages of PMN in the different anatomical sites are relatively similar from case to case. Various workers have suggested that analysis of the cell types present in bronchopulmonary lavage can be used as a therapeutic index, or as a diagnostic test. Our data suggest that lavage does indeed sample the lower airways and alveolar spaces, and that such usage may well be justified.

Animals↗
PubMed1987

An enzyme-linked immunoassay for nerve growth factor (NGF): a tool for studying regulatory mechanisms involved in NGF production in brain and in peripheral tissues.

A sensitive enzyme-linked immunosorbent assay (ELISA) for nerve growth factor (NGF) has been developed. The sensitivity of this assay (0.1 pg/well) permits the quantification of endogenous immunoreactive NGF in the peripheral nervous system and the CNS. Studies on the regulatory mechanisms involved in NGF production indicate that, in addition to neurally mediated mechanisms, other stimuli, e.g., inflammation, significantly contribute to NGF production.

Animals↗
PubMed2006

In vivo selective binding of (R)-[11C]rolipram to phosphodiesterase-4 provides the basis for studying intracellular cAMP signaling in the myocardium and other peripheral tissues.

INTRODUCTION: Phosphodiesterase-4 (PDE4) enzymes specifically break down the second messenger cAMP, thereby terminating the intracellular signaling cascade that plays an essential role in neurohormonal modulation of many physiological systems. PDE4 activity and expression are regulated by cAMP levels, suggesting that measurement of PDE4 provides an index of intracellular cAMP signaling. METHODS: Male Sprague-Dawley rats were administered (R)- or the less active enantiomer (S)-[11C]rolipram and sacrificed 30 min later with tracer retention measured in various tissues. Co-injections with saturating doses of unlabeled (R)-rolipram, (S)-rolipram and Ro 20-1724, as well as subtype-selective PDE inhibitors vinpocetine, Bay 60-7550, cilostazol and zaprinast were used to establish binding selectivity for PDE4 over PDE1, PDE2, PDE3 and PDE5 subtypes, respectively. Autoradiography was performed to substantiate results of biodistribution studies in the myocardium. RESULTS: In vivo (R)-[11C]rolipram retention was dose-dependently reduced by co-injections of (R)-rolipram and (S)-rolipram (ED50 values of 0.03 mg/kg and 0.2 mg/kg, respectively). Vinpocetine, Bay 60-7550, cilostazol and zaprinast had no effect on (R)-[11C]rolipram binding, while (R)-rolipram and Ro 20-1724 reduced the tracer uptake to nonspecific levels in PDE4-rich tissues. CONCLUSIONS: In addition to the brain, (R)-[11C]rolipram binds selectively to PDE4 across all cardiac regions, skeletal muscle, lungs and pancreas, but not in the adipose tissues. In vivo findings were confirmed by in vitro autoradiography studies, suggesting that (R)-[11C]rolipram can be applied to evaluate alterations in central and peripheral PDE4 levels and cAMP-mediated signaling.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1984

Resistance of peripheral tissues and pituitary to thyroid hormone.

We describe a 29-year-old male with thyroid hormone resistance. He was first seen because of a goiter, and was considered to have hyperthyroid Graves' disease. Despite subtotal thyroidectomy followed by radioiodine therapy, serum thyroxine levels were elevated with high serum TSH levels. Baseline thyroid function showed serum thyroxine of 16.6 micrograms/dl, free thyroxine of 4.60 ng/dl, triiodothyronine of 197 ng/dl, and TSH of 34 microU/ml. Triiodothyronine administration by gradually increased doses of 75, 150, 225, 300, and 375 micrograms/d over a 25-day period resulted in gradual reduction of serum TSH and T4 levels, but serum TSH still responded to TRH even during this period. The basal metabolic rate was--14% and showed a minimal rise even with large doses of triiodothyronine. The results led to the diagnosis of generalized thyroid hormone resistance including the pituitary gland. Increased pulse rate, finger tremor and emotional lability in the patient suggest that the severity of peripheral refractoriness to the hormone may vary from tissue to tissue. In addition, a reduced thyroidal responsiveness to TSH as a consequence of inappropriate radioiodine therapy was observed in this patient.

Adult↗
PubMed1987

Blunted peripheral tissue responsiveness to thyroid hormone in uremic patients.

To understand the biologic significance of the low triiodothyronine (T3) syndrome in patients with chronic renal failure (CRF), we examined thyroid hormone profile, basal O2 uptake (VO2), and peripheral blood mononuclear leukocyte (PBL) ouabain binding in these patients and in the control subjects before and after L-triiodothyronine (T3) and sodium ipodate treatment. In the controls (N = 8), T3 administration increased serum total T3 from 136 +/- 15 to 232 +/- 11 ng/dl, and reduced total thyroxine (T4) from 8.14 +/- 0.56 to 6.08 +/- 0.43 micrograms/dl, free T4 from 1.59 +/- 0.12 to 1.03 +/- 0.05 ng/dl and thyroid-stimulating hormone (TSH) from 1.74 +/- 0.24 to 0.41 +/- 0.09 microU/ml. VO2 increased from 2.66 +/- 0.11 to 3.15 +/- 0.09 ml/kg/min. Ipodate treatment, on the other hand, resulted in a reduction of serum total T3 to 102 +/- 21 ng/dl, an increase in total T4 to 9.59 +/- 0.50 micrograms/dl, free T4 to 1.91 +/- 0.13 ng/dl and TSH to 3.64 +/- 1.14 microU/ml. VO2 decreased to 2.43 +/- 0.06 ml/kg/min. P values ranged from less than 0.05 to less than 0.001. In the CRF patients (N = 14), T3 treatment also resulted in a rise in serum total T3 from 75 +/- 5 to 185 +/- 8 ng/dl. Total T4 declined from 6.68 +/- 0.34 to 5.18 +/- 0.48 micrograms/dl, free T4 from 0.85 +/- 0.1 to 0.67 +/- 0.08 ng/dl and TSH from 3.67 +/- 0.86 to 0.94 +/- 0.3 microU/ml. VO2, however, did not change (from 2.91 +/- 0.12 to 2.99 +/- 0.17 ml/kg/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1978

Peptide neurons in peripheral tissues including the urinary tract: immunohistochemical studies.

Using the indirect immunofluorescence technique of Coons and collaborators, neurons containing substance P-, enkephalin-, vasoactive intestinal polypeptide (VIP)--and somatostatin-like immuno-reactivity have been identified in the peripheral nervous system. They have a widespread distribution, particularly in the gastrointestinal and urinary tracts. Whereas part of these peptide containing fibres may belong to sensory neurons, the majority seem to have their origin in peripheral autonomic ganglia, indicating a complex built up of the autonomic nervous system. There is evidence that some noradrenergic neurons contain somatostatin, which may suggest that one neuron can synthesize and store two transmitters. The significance of such neurons, as well as of peripheral peptide neurons in general, remains to be elucidated.

Angiotensin II↗
PubMed1985

Viscous factors in peripheral tissue perfusion.

To ascertain the relative importance of the factors that influence blood viscosity (VIS), we measured hematocrit (HCT), filterability index, fibrinogen level (FIB), and Ektacytometer indices at osmolarities of both 290 (EI 290) and 200 (EI 200) in 21 diabetic patients with peripheral vascular disease (DPVDs) and 11 healthy volunteers (HVs). Stepwise multiple regression analyses generated a formula based on three of the independent variables (FIB, HCT, EI 200) that accurately predicted VIS (r = 0.79, p less than 0.01). Based on the beta coefficients and F statistics, HCT and FIB were the most important elements in the linear regression equation. Compared with HVs the total group of DPVDs had lower HCT (36.5% vs. 42.4%) and higher FIB (661 vs. 276 mg/dl, p less than 0.01) values. When all HVs were compared with a subgroup of DPVDs with similar HCT (n = 10), both FIB and VIS were higher (p less than 0.001) in the DPVD than in the HV group. We conclude that the most important of the multiple factors that influence VIS are HCT and FIB. The finding of increased FIB in DPVDs could have important implications for drug and surgical therapy in this group of patients.

Blood Circulation↗
PubMed1983

Immunoelectron microscopic localization of rabies virus antigen in central nervous system and peripheral tissue using low-temperature embedding and protein A-gold.

A protein A-gold technique was used in conjunction with low temperature embedding to visualize ultrastructurally mature virions and sites of viral replication in the brains of rabies virus-infected mice after peripheral inoculation of virus. The association of viral profiles and gold particles with synaptic membranes, microtubules and rough endoplasmic reticulum suggested a mechanism of rabies virus transport within the central nervous system. Early interactions of inflammatory cells with the virus inoculum were characterized by phagocytosis by non-degranulating neutrophils and mononuclear cells.

Animals↗
PubMed2001

Expression of a tolerizing tumor antigen in peripheral tissue does not preclude recovery of high-affinity CD8+ T cells or CTL immunotherapy of tumors expressing the antigen.

Transgenic (TG) mice were generated selectively expressing the gag protein of Friend murine leukemia virus (FMuLV) in the liver. FMuLV(gag) is also expressed by the FBL leukemia, and is the immunodominant tumor Ag of the CD8(+) T cell response in C57BL/6 mice. gag-TG mice expressing FMuLV(gag) in the liver were tolerant to the protein and failed to generate a CTL response to either FBL or FMuLV(gag). This tolerance reflected anergy rather than deletion, as CTL responsiveness could be recovered after four cycles of in vitro stimulation. Adoptively transferred gag-specific T cells were not anergized in gag-TG recipients, as revealed by antitumor activity in vivo. Also, such T cells did not induce detectable autoimmune injury in gag-TG liver cells. These results suggest that the requirements for a tissue Ag to provide a tolerizing stimulus are distinct from those for being the target of a T cell-mediated autoimmune response and that the requirements for induction and maintenance of peripheral tolerance are distinct for naive and primed T cells. That anergic T cells reactive with tumor-associated Ags can be recovered by repetitive in vitro stimulation and can mediate tumor therapy suggests strategies that use such Ags to generate CTL for adoptive immunotherapy should be further developed.

Animals↗
PubMed2006

Evidence for the presence of thyroid stimulating hormone, thyroglobulin and their receptors in Eisenia fetida: a multilevel hormonal interface between the nervous system and the peripheral tissues.

The present study describes the localization and distribution of thyroid-stimulating hormone (TSH), thyroglobulin (TGB) and their receptors in Eisenia fetida (Annelida, Oligochaeta) as revealed by immunohistological methods. Immunopositive neuronal and non-neuronal cells are present in both the central nervous system and some peripheral organs (e.g. foregut and coelomocytes). TSH- and TGB-immunopositive neurons in the various ganglia of the central nervous system are differentially distributed. Most of the immunoreactive cells are found in the suboesophageal ganglion. The stained cells also differ in their shapes (round, oval, pear-shaped) and sizes (small, 12-25 microm; medium, 20-35 microm; large, 30-50 microm). In all ganglia of the central nervous system, TSH-positive neurons additionally show gamma aminobutyric acid (GABA) immunopositivity. Non-neuronal cells also take part in hormone secretion and transport. Elongated TSH-positive cells have been detected in the capsule of the central ganglia and bear granules or vacuoles in areas lacking neurons. Many of capillaries show immunoreactivity for all four tested antibodies in the entire central nervous system and foregut. Among the coelomocytes, granulocytes and eleocytes stain for TSH and its receptor and for TGB but not for thyroid hormone receptor. Most of the granulocytes are large (25-50 microm) but a population of small cells (10-25 microm) are also immunoreactive. None of the coelomocytes stain for GABA. We therefore suggest that the members of this hormone system can modify both metabolism and immune functions in Eisenia. Coelomocytes might be able to secrete, transport and eliminate hormones in this system.

Animals↗
PubMed1996

Expression of three glutamate transporter subtype mRNAs in human brain regions and peripheral tissues.

We compared the expression of mRNAs for three human glutamate transporter subtypes in human central nervous system (CNS) and other organs by Northern blot analysis. hGLT-1 and hGLuT-1 mRNAs were most abundantly expressed in the brain, while hEAAC1 mRNA expression (3.8 kb and 2,4 kb) was strongest in peripheral organs. All subtype mRNAs were expressed throughout the CNS with hGLT-1 predominant in frontal lobe, striatum and limbic areas, and hGluT-1 predominant in cerebellum.

ATP-Binding Cassette Transporters↗