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Fufang Meidengmu (FFMDM) is an ethnic herbal medicine form Yunnan province of China, which is often used for the treatment of uterine leiomyoma (UL). Combined Gancao (Glycyrrhiza uralensis Fisch.) and Haizao (Sargassum pallidum (Turn.) C.Ag) in FFMDM represent an herbal pair in the so-called “eighteen antagonistic medicaments” according to traditional Chinese medicine. In this study, we explored the prevention and treatment effects of FFMDM component compatibility on UL in mice. Female Kunming mice were injected for different periods of time with different concentrations of estradiol benzoate (EB) to investigate a feasible method to establish a mice model of UL. Treatment with 0.3mg/kg EB for 15 days was found to be the optimal condition for UL mice models. We then investigate the role of Gancao and Haizao in FFMDM, and explored the underlying mechanism of action of UL mice. Our findings suggested that Gancao and Haizao exerted the favorable effects. In addition, FFMDM is effective in the treatment of UL, and its mechanism was associated with the estrogen (ER) and progesterone receptors (PR). [ABSTRACT FROM AUTHOR]

Thyroid hormones have developmental effects during fetal life. Fetal hypothyroidism leads to glucose intolerance and reduced insulin secretion capacity. Activity of nitric oxide synthases follows a heterogeneous pattern in hypothyroidism. Overactivity of constitutive nitric oxide synthase (NOS), inhibits glucose-stimulated insulin release. The aim of this study was to examine if reduction in insulin secretion in fetal hypothyroidism is due to overproduction of nitric oxide. Pregnant Wistar rats were divided into 2 groups; the experimental group consumed water containing 0.02 % of 6-propyl-2-thiouracil till delivery, while the control group consumed tap water. After delivery serum thyroid hormones were measured. Intravenous glucose tolerance test was performed in 6-month old offspring (n = 8). After 3 weeks recovery, pancreatic islets were isolated and insulin secretion, inducible and constitutive nitric oxide synthase activity were measured (n = 4). Compared to controls, during intravenous glucose tolerance test, fetal hypothyroid rats had high plasma glucose concentration (p = 0.003) and low plasma insulin levels (p = 0.012) at 5-20 min and their insulin secretion from isolated islets at basal glucose concentration and in the presence of l-arginine was lower. The nitric oxide synthase inhibitor, NG-nitrol-arginine methyl ester significantly improved insulin secretion in fetal hypothyroid rats at basal glucose concentration and in the presence of l-arginine. The results showed higher NOS activities in fetal hypothyroid rats (constitutive ± 1.09 vs. 47.34 ± 4.44 and inducible 4.09 ± 0.96 vs. 19.97 ± 1.14 pmol/min/mg proteins, p = 0.002). In conclusion, NO overproduction through NOS participates in decreased insulin secretion in fetal hypothyroid rats. [ABSTRACT FROM AUTHOR]

Tetrahydrobiopterin (BH 4 ) is an essential cofactor of nitric oxide synthase (NOS), and reduced BH 4 availability leads to endothelial NOS (eNOS) uncoupling and increased reactive oxygen species (ROS) generation. Questions remain regarding the functional state of eNOS and role of BH 4 availability in the process of in vivo myocardial ischemia–reperfusion (I/R) injury. Rats were subjected to 60 min of in vivo left coronary artery occlusion and varying periods of reperfusion with or without pre-ischemic liposomal BH 4 supplementation (1 mg/kg, iv). Myocardial infarction was correlated with cardiac BH 4 content, eNOS protein level, NOS enzyme activity, and ROS generation. In the vehicle group, 60-min ischemia drastically reduced myocardial BH 4 content in the area at risk (AAR) compared to non-ischemic (NI) area and the level remained lower during early reperfusion followed by recovery after 24-h reperfusion. Total eNOS, activated eNOS protein level (eNOS Ser1177 phosphorylation) and NOS activity were also significantly reduced during ischemia and/or early reperfusion, but recovered after 24-h reperfusion. With liposomal BH 4 treatment, BH 4 levels were identical in the AAR and NI area during ischemia and/or early reperfusion, and were significantly higher than with vehicle. BH 4 pre-treatment preserved eNOS Ser1177 phosphorylation and NOS activity in the AAR, and significantly reduced myocardial ROS generation and infarction compared to vehicle. These findings provide direct evidence that in vivo I/R induces eNOS dysfunction secondary to BH 4 depletion, and that pre-ischemic liposomal BH 4 administration preserves eNOS function conferring cardioprotection with reduced oxidative stress. [ABSTRACT FROM AUTHOR]

ObjectiveWe investigated whether the nitric oxide (NO) precursor, l-arginine, can prevent the antidepressant-like action of the fast-acting antidepressant, ketamine, in a genetic rat model of depression, and/or induce changes in the glutamate (Glu)/N-methyl-d-aspartate receptor (NMDAR)/NO/cyclic guanosine monophosphate (cGMP) signalling pathway. Hereby it was evaluated whether the NO signalling system is involved in the antidepressant mechanism of ketamine.MethodsFlinders sensitive line (FSL) rats received single i.p. injections of ketamine (15 mg/kg) with/without pre-treatment (30 min prior) with l-arginine (500 mg/kg). Depression-like behaviour was assessed in the forced swim test (FST) in terms of immobility, and the activation state of the Glu/NMDAR/NO/cGMP pathway was evaluated ex vivo in the frontal cortex and hippocampus regions in terms of total constitutive NOS (cNOS) activity and cGMP concentration.Resultsl-Arginine pre-treatment prevented the antidepressant-like effect of ketamine in the FST, as well as a ketamine-induced increase in cGMP levels in the frontal cortex and hippocampus of FSL rats. Ketamine reduced cNOS activity only in the hippocampus, and this effect was not reversed by l-arginine.ConclusionBoth the behavioural and molecular results from this study indicate an involvement for the NO signalling pathway in the antidepressant action of ketamine. Although not easily interpretable, these findings broaden our knowledge of effects of ketamine on the NO system. [ABSTRACT FROM PUBLISHER]

The objective of this study was to investigate the biochemical changes of nitric oxide synthase (NOS) in pork skeletal muscles during postmortem storage. Longissimus thoracis (LT), psoas major (PM) and semimembranosus (SM) muscles of pork were removed immediately after slaughter and stored under vacuum condition at 4 °C for 0, 1 and 3 d. Results showed that all three muscles exhibited NOS activity until 1 d while SM muscle retained NOS activity after 3 d of storage. The content of nNOS in SM muscle was stable across 3 d of storage while decreased intensity of nNOS was detected at 1 and 3 d of aging in PM and LT muscles due to the degradation of calpain. Immunostaining showed that nNOS was located at not only sarcolemma but also cytoplasm at 0 and 1 d of storage. Our data suggest that postmortem muscles possess NOS activity and nNOS expression depends on muscle type. [ABSTRACT FROM AUTHOR]

The present study tested the hypothesis that spontaneously hypertensive rats ( SHR) have impaired nitric oxide synthase ( NOS)-mediated regulation of vascular function versus Wistar-Kyoto rats ( WKY). Aorta and small mesenteric arteries were studied from male and female SHR (M SHR and F SHR) and WKY (M WKY and F WKY). Phenylephrine ( PE)-induced vasoconstriction was greater in aorta of M SHR versus all others ( P < 0.05); there were neither sex nor strain differences in PE contraction in mesenteric arteries. The NOS inhibitor l-Nitro-Arginine Methyl Ester ( l- NAME) increased PE-induced vasoconstriction in all rats, although the increase was the least in male SHR ( P < 0.05), revealing a blunted vasoconstrictor buffering capacity of NOS. l- NAME increased sensitivity to PE-induced constriction only in mesenteric arteries of SHR, although, the maximal percent increase in contraction was comparable among groups. ACh-induced relaxation was also less in aorta from M SHR versus all others ( P < 0.05). ACh relaxation was comparable among groups in mesenteric arteries, although SHR exhibited a greater NOS component to ACh-induced relaxation than WKY. To gain mechanistic insight into sex and strain differences in vascular function, NOS activity and NOS3 protein expression were measured. Aortic NOS activity was comparable between groups and M SHR had greater NOS3 expression than M WKY. In contrast, although vascular function was largely maintained in mesenteric arteries of SHR, NOS activity was less in SHR versus WKY. In conclusion, M SHR exhibit a decrease in NOS regulation of vascular function compared to F SHR and WKY, although this is not mediated by decreases in NOS activity and/or expression. [ABSTRACT FROM AUTHOR]

Stress induced by ultraviolet-B (UV-B) irradiation stimulates the accumulation of various secondary metabolites in plants. Nitric oxide (NO) serves as an important secondary messenger in UV-B stress-induced signal transduction pathways. NO can be synthesized in plants by either enzymatic catalysis or an inorganic nitrogen pathway. The effects of UV-B irradiation on the production of baicalin and the associated molecular pathways in plant cells are poorly understood. In this study, nitric oxide synthase (NOS) activity, NO release and the generation of baicalin were investigated in cell suspension cultures of Scutellaria baicalensis exposed to UV-B irradiation. UV-B irradiation significantly increased NOS activity, NO release and baicalin biosynthesis in S. baicalensis cells. Additionally, exogenous NO supplied by the NO donor, sodium nitroprusside (SNP), led to a similar increase in the baicalin content as the UV-B treatment. The NOS inhibitor, NW-nitro-L-arginine (LNNA), and NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) partially inhibited UV-B-induced NO release and baicalin accumulation. These results suggest that NO is generated by NOS or NOS-like enzymes and plays an important role in baicalin biosynthesis as part of the defense response of S. baicalensis cells to UV-B irradiation. [ABSTRACT FROM AUTHOR]

Abstract: Background: There may be a relationship between endothelial dysfunction, coagulation activation and nitric oxide (NO) synthesis in women with mild and severe preeclampsia (PE). Methods: Plasma thrombomodulin (TM), D-Dimer (D-Di), cyclic guanosine monophosphate (cGMP) and placental nitric oxide synthase activity (NOS) were investigated in 21 normotensive pregnant women (G1), 22 pregnant women with mild PE (G2) and 20 pregnant women with severe PE (G3). Results: TM and D-Di were significantly increased in G3 compared to G1 (P =0.001 and P =0.006, respectively) and G2 (P =0.001, in both cases). However, there was no significant difference when G1 was compared to G2. For total NOS, calcium independent NOS, calcium dependent NOS no significant difference was observed among the groups studied. Conclusions: TM and D-Di levels are raised in women with severe PE compared to normotensive pregnant women and women with mild PE. While increased TM levels may reflect endothelial dysfunction, raised D-Di levels indicate a hypercoagulable state. NO assessed by 2 indirect methods did not show any significant difference among the groups studied. Due to current limitations with in vitro NO measurements and interferences associated with NO bioavailability, particularly in PE, such findings should not be over-interpreted. [Copyright &y& Elsevier]

Abstract: The importance of the nitric oxide synthase (NOS) gene family is demonstrated by many studies in vertebrates and invertebrates in recent years. However, it keeps unknown of nitric oxide (NO) system and NOS gene family in mud crab Scylla paramamosain, an important cultured commercial crustacean in China and Pacific area. In this report, the cDNA of NOS containing full-length ORF was cloned from mud crab, S. paramamosain. It was of 4424 bp, including a 5′-terminal untranslated region (UTR) of 239 bp, a 3′-terminal UTR of 540 bp, which contained two ATTTA motifs, and an open reading frame (ORF) of 3645 bp encoding a polypeptide of 1214 amino acids. Structural analysis indicated that NOS contained a typical NO synthase domain at the N-terminal, next to a flavodoxin 1 domain, a flavin adenine dinucleotide (FAD) binding domain, respectively, and a conservative nicotinamide adenine dinucleotide (NAD) binding domain structure at the C-terminal. Quantitative real-time PCR analysis revealed S. paramamosain NOS (SpNOS) to be expressed in all tissues examined, with the highest expression in midintestine and the weakest level in heart and eyestalk. The expression profiles of SpNOS indicated that the NOS expression levels were significantly induced in midintestine, hepatopancrease and hemocytes after challenged with Vibrio Parahaemolyticus, the synthetic double-stranded RNA polyinosinic polycytidylic acid (poly I:C) and lipopolysaccharides (LPS). The NOS activity in hemocytes showed significant increase during at 24 h–48 h time period after immune challenges with V. Parahaemolyticus, poly I:C and LPS. Results here may suggest that the inducible NOS play an important role in mud crab’s defense against pathogenic infection. [Copyright &y& Elsevier]

Abstract: Preventive or therapeutic effects of caffeic acid in brain of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treated mice against inflammatory injury were examined. Caffeic acid at 0.5, 1 or 2% was supplied either pre-intake or post-intake for 4weeks. Brain caffeic acid content was increased by caffeic acid pre-intake at 1 and 2%, and post-intake at 2% (P <0.05). MPTP treatment enhanced the release of interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)-alpha, IL-4 and IL-10 (P <0.05). Pre-intake of caffeic acid decreased the production of test cytokines (P <0.05); however, post-intake only at 2% reduced the level of IL-1beta, IL-6 and TNF-alpha (P <0.05). MPTP treatment up-regulated mRNA expression of inducible nitric oxide synthase (iNOS), neuronal NOS, cyclooxygenase (COX)-2, glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1, and increased production of nitric oxide (NO) and prostaglandin E2 (PGE2) (P <0.05). Caffeic acid pre-intake at test doses and post-intake at 2% declined the expression of iNOS, COX-2 and GFAP; and lowered the production of NO and PGE2 (P <0.05). MPTP treatment suppressed mRNA expression of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor and tyrosine hydroxylase (TH), and lowered dopamine level (P <0.05). Caffeic acid pre-intake retained the expression of these factors, maintained TH activity and protein production, and dopamine synthesis (P <0.05). These results suggest that caffeic acid is a potent neuroprotective agent against the development of Parkinson''s disease. [Copyright &y& Elsevier]

Abstract: Systemic lipopolysaccharide (LPS) administration induces an innate immune response and stimulates the hypothalamic–pituitary–adrenal axis. We studied Angiotensin II AT1 receptor participation in the LPS effects with focus on the pituitary gland. LPS (50μg/kg, i.p.) enhanced, 3h after administration, gene expression of pituitary CD14 and that of Angiotensin II AT1A receptors in pituitary and hypothalamic paraventricular nucleus (PVN); stimulated ACTH and corticosterone release; decreased pituitary CRF1 receptor mRNA and increased all plasma and pituitary pro-inflammatory factors studied. The AT1 receptor blocker (ARB) candesartan (1mg/kg/day, s.c. daily for 3days before LPS) blocked pituitary and PVN AT1 receptors, inhibited LPS-induced ACTH but not corticosterone secretion and decreased LPS-induced release of TNF-α, IL-1β and IL-6 to the circulation. The ARB reduced LPS-induced pituitary gene expression of IL-6, LIF, iNOS, COX-2 and IκB-α; and prevented LPS-induced increase of nNOS/eNOS activity. The ARB did not affect LPS-induced TNF-α and IL-1β gene expression, IL-6 or IL-1β protein content or LPS-induced decrease of CRF1 receptors. When administered alone, the ARB increased basal plasma corticosterone levels and basal PGE2 mRNA in pituitary. Our results demonstrate that the pituitary gland is a target for systemically administered LPS. AT1 receptor activity is necessary for the complete pituitary response to LPS and is limited to specific pro-inflammatory pathways. There is a complementary and complex influence of the PVN and circulating cytokines on the initial pituitary response to LPS. Our findings support the proposal that ARBs may be considered for the treatment of inflammatory conditions. [Copyright &y& Elsevier]

Abstract: The effect of resveratrol on activity and expression of nitric oxide synthase (NOS) in the spinal cord of neuropathic rats was assessed. Spinal nerve ligation produced tactile allodynia along with a reduction of catalytic activity of the constitutive Ca2+-dependent NOS (eNOS and nNOS isoforms) in the ipsilateral dorsal horn, but not contralateral dorsal or ipsilateral or contralateral ventral, spinal cord at 1, 5, 10 and 15 days after surgery compared to naïve and sham-operated animals. Nerve ligation also induced a reduction of nNOS expression in the ipsilateral dorsal horn spinal cord at 10 and 15 days after surgery. Intrathecal resveratrol reduced allodynia and reversed the reduction of constitutive Ca2+-dependent NOS activity in the ipsilateral dorsal spinal cord. Moreover, resveratrol significantly reversed the reduction of nNOS expression in the ipsilateral dorsal horn spinal cord. Results show that spinal nerve ligation leads to development of tactile allodynia along with a reduction in constitutive Ca2+-dependent NOS activity and nNOS isoform expression in the ipsilateral dorsal horn. Data suggest that resveratrol may reduce tactile allodynia in neuropathic rats by restoring altered NOS activity and expression. [Copyright &y& Elsevier]

Abstract: Sciatic axotomy in 2-day-old rats (P2) causes lumbar motoneuron loss, which could be associated with nitric oxide (NO) production. NO may be produced by three isoforms of synthase (NOS): neuronal (nNOS), endothelial (eNOS) and inducible (iNOS). We investigated NOS expression and NO synthesis in the lumbar enlargement of rats after sciatic nerve transection at P2 and treatment with the antioxidant melatonin (sc; 1mg/kg). At time points ranging from P2 to P7, expression of each isoform was assessed by RT-PCR and immunohistochemistry; catalytic rates of calcium-dependent (nNOS, eNOS) and independent (iNOS) NOS were measured by the conversion of [3H]l-arginine to [3H]l-citrulline. All NOS isoforms were expressed and active in unlesioned animals. nNOS and iNOS were detected in some small cells in the parenchyma. Only endothelial cells were positive for eNOS. No NOS isoform was detected in motoneurons. Axotomy did not change these immunohistochemical findings, nNOS and iNOS mRNA expression and calcium-independent activity at all survival times. However, sciatic nerve transection reduced eNOS mRNA levels at P7 and increased calcium-dependent activity at 1 and 6h. Melatonin did not alter NOS expression. Despite having no action on NOS activity in unlesioned controls the neurohormone enhanced calcium-dependent activity at 1 and 72h and reduced calcium-independent catalysis at 72h in lesioned rats. These results suggest that NOS isoforms are constitutive in the neonatal lumbar enlargement and are not overexpressed after sciatic axotomy. Changes in NO synthesis induced by axotomy and melatonin administration in the current model are discussed considering some beneficial and deleterious effects that NO may have. [Copyright &y& Elsevier]

Abstract: Redox-active metals are of paramount importance for biological functions. Their impact and cellular activities participate in the physiological and pathophysiological processes of the central nervous system (CNS), including inflammatory responses. Manganese is an essential trace element and it is required for normal biological activities and ubiquitous enzymatic reactions. However, excessive chronic exposure to manganese results in neurobehavioral deficits. Recent evidence suggests that manganese neurotoxicity involves activation of microglia or astrocytes, representative CNS immune cells. In this study, we assessed the molecular basis of the effects of manganese on the modulation of pro-inflammatory cytokines and nitric oxide (NO) production in primary rat cortical glial cells. Cultured glial cells consisted of 85% of astrocytes and 15% of microglia. Within the assayed concentrations, manganese was unable to induce tumor necrosis factor α (TNF-α) and inducible nitric oxide synthase (iNOS) expression, whereas it potentiated iNOS and TNF-α gene expression by lipopolysaccharide/interferon-γ-activated glial cells. The enhancement was accompanied by elevation of free manganese, generation of oxidative stress, activation of mitogen-activated protein kinases, and increased NF-κB and AP-1 binding activities. The potentiated degradation of inhibitory molecule IκB-α was one of underlying mechanisms for the increased activation of NF-κB by manganese. However, manganese decreased iNOS enzymatic activity possibly through the depletion of cofactor since exogenous tetrahydrobiopterin reversed manganese''s action. These data indicate that manganese could modulate glial inflammation through variable strategies. [Copyright &y& Elsevier]

Background: Nitric oxide (NO), synthesized by neuronal (nNOS), endothelial (eNOS), and inducible (iNOS) nitric oxide synthases, plays an essential role in the physiological functions of the gastrointestinal (GI) tract. Chronic ethanol intake has been shown to interfere with several of these physiological functions, leading to the pathological alterations observed in alcoholic individuals. Our aim therefore was to investigate the effects of chronic ethanol consumption on NOS isoforms in different GI segments. Methods: Rats received either 20% aqueous ethanol solution or water for 8 weeks. Tissue samples of the duodenum, jejunum, ileum, and colon of the rats were used for measurement of the NOS activity, protein content, and nNOS immunohistochemistry. Anti-HuC/D immunohistochemistry was used to determine the total number of neurons. Results: Measurement of the physiological constitutive NOS (cNOS) activity revealed a 20 times higher activity in the colon than in the small intestine and after chronic ethanol treatment demonstrated a significant decrease in the jejunum, ileum, and colon, while in the duodenum it remained unchanged compared with the control group. The physiological iNOS activity was higher in the ileum and colon than in the duodenum and jejunum, and these levels were not significantly affected by ethanol. Neuronal nitric oxide synthase immunohistochemistry revealed a significant decrease in the numbers of immunostained cells in all investigated intestinal segments, while the total number of myenteric neurons remained constant. The nNOS protein content measured by Western blotting indicated a significant decrease in the colon after ethanol consumption, while in other intestinal segments change was not detectable. Conclusions: This study has demonstrated for the first time that chronic ethanol consumption has a differential effect on NOS activity, NOS protein content, and the number of nitrergic neurons in different intestinal segments, suggesting that chronic ethanol administration affects the NO pathways in the enteric nervous system. [ABSTRACT FROM AUTHOR]

Abstract: The effects of ultraviolet-B (UV-B) radiation on stem elongation growth, xyloglucan-degrading activity, the rate of nitric oxide (NO) release and nitric oxide synthase (NOS) activity were evaluated in stems of pea (Pisum sativum L.) seedlings during a 5 days growth period. UV-B radiation significantly induced NOS activity and promoted NO release subsequently inhibited xyloglucan-degrading activity which led to the inhibition of pea stems elongation. Similarly, exogenous NO donation to the rhizospheric zone of pea seedlings imitated the responses of stems to UV-B radiation. NOS inhibitor (LNNA) and NO scavenger (PTIO) had the opposite responses to UV-B radiation: decrease NO release, increase xyloglucan-degrading activity and stems elongation. The results indicated that reduction of stems length caused by UV-B radiation was possibly achieved through modification of the mechanical properties of cell wall polysaccharides, which was probably mediated by the change of xyloglucan-degrading activities in cell walls and NO might be as a signal regulating the xyloglucan-degrading activities in cell walls. In addition, the difference of NOS origin between graminaceous plants and dicots was discussed. [Copyright &y& Elsevier]

Many authors hypothesize that the epidermal growth factor (EGF) is involved in the onset of labor. Previous reports from our laboratory showed that intrauterine administration of EGF delays the beginning of labor. The aims of this study were: 1) to analyze the effect of intrauterine administration of 500ng EGF on placental prostaglandins and nitric oxide, and 2) to characterize the expression of EGF receptors (EGF-R) in pregnant rat placentae. Saline solution (sham group) and 500ng EGF (EGF-treated group) were administered via intrauterine injection on day 21 of gestation, and both groups of animals were sacrificed on day 22 (sham rats delivered on day 22). Results showed that EGF treatment: 1) inhibited the production of prostaglandin E (p <0.001) and F2α (p <0.01), 2) increased the synthesis of nitric oxide (p <0.001), and 3) reduced the expression of cyclooxygenase-II, the enzyme responsible for PG synthesis. Placentae were found to express EGF-R and its activated form, and the expressions of both forms were higher at mid and term pregnancy. Hence, EGF is a very interesting molecule for studying the regulation of placental prostaglandin and nitric oxide production related to the parturition process. [Copyright &y& Elsevier]

We demonstrated the presence of circulating antibodies from Sjögren syndrome (SS) patients enable to interact with rat cerebral frontal cortex by activating muscarinic acetylcholine receptors (mAChRs). IgG from SS and IgG from normal subjects were studied by flow cytometry, enzyme immunoassay (ELISA), and radioligand binding assays. By flow cytometric and ELISA procedures, it was shown that IgG from SS patients reacted to cerebral frontal cortex cell surface. SS IgG was able to interact with mAChR by inhibiting 3H-QNB binding to its specific receptor. Besides, SS IgG displayed an agonistic-like activity associated to specific M1 and M3 mAChR activation, increasing nitric oxide synthase (NOS) isoform activities. Neuronal (n) and endothelial (e) NOS-mRNA gene expression of rat frontal cortex is induced by SS IgG. This article supports the participation of humoral immune alterations in SS, resulting in central parasympathetic functional deregulation. These antibodies alter mAChR activation, NOS activity, and eNOS and nNOS gene expression. [Copyright &y& Elsevier]

This study provides evidence that, in the preoptic–hypothalamo–hypophysial system of the teleost Oreochromis niloticus, several sub-populations of arginine–vasotocin (AVT)-producing neurons and neurosecretory fibers terminals express neuronal nitric oxide synthase (nNOS)-like molecules. The co-localization between nNOS and AVT was demonstrated by means of double immunofluorescence staining with the confocal microscope. This study is the first to provide evidence that nNOS may be co-localized with AVT in neurons of a non-mammalian vertebrate. [Copyright &y& Elsevier]

Research on NO in plants has gained considerable attention in recent years mainly due to its function in plant growth and development and as a key signalling molecule in different intracellular processes in plants. The NO emission from plants is known since the 1970s, and now there is abundant information on the multiple effects of exogenously applied NO on different physiological and biochemical processes of plants. The physiological function of NO in plants mainly involves the induction of different processes, including the expression of defence-related genes against pathogens and apoptosis/programmed cell death (PCD), maturation and senescence, stomatal closure, seed germination, root development and the induction of ethylene emission. NO can be produced in plants by non-enzymatic and enzymatic systems. The NO-producing enzymes identified in plants are nitrate reductase, and several nitric oxide synthase-like activities, including one localized in peroxisomes which has been biochemically characterized. Recently, two genes of plant proteins with NOS activity have been isolated and characterized for the first time, and both proteins do not have sequence similarities to any mammalian NOS isoform. However, different evidence available indicate that there are other potential enzymatic sources of NO in plants, including xanthine oxidoreductase, peroxidase, cytochrome P450, and some hemeproteins. In plants, the enzymatic production of the signal molecule NO, either constitutive or induced by different biotic/abiotic stresses, may be a much more common event than was initially thought. [Copyright &y& Elsevier]

In the present study, we have analyzed the expression of nitric oxide synthase (NOS) in the preoptic-hypothalamo-hypophyseal system of the teleost Oreochromis niloticus. The assay for enzyme activity demonstrated that a constitutive NOS activity is present both in soluble and particulate fractions of the homogenates of diencephalons. Western blot analysis using an antibody against the N-terminus of human nNOS revealed two bands both in the supernatant and in the pellet. One band co-migrates at approximately 150 kDa with that detected in the rat cerebellum homogenates and presumably corresponds to neuronal NOS (nNOS) of mammals. The additional band, which migrates at approximately 180 kDa, might be attributed to an alternatively spliced nNOS isoform. Using NADPH diaphorase (NADPHd) histochemistry in combination with NOS immunohistochemistry, nNOS expression has been detected in preoptic nuclei, hypophysiotrophic nuclei of the ventral hypothalamus, and the pituitary gland. Various degrees of dissociation of NADPHd activity and nNOS immunoreactivity have been detected that could be attributed to the expression of different subtypes of nNOS in the preoptic/hypothalamo/hypophysial system of tilapia. In this paper, we also investigated the colocalization of nNOS with arginine-vasotocin (AVT) by means of immunolabeling of consecutive sections. Results suggest that NO may be colocalized with AVT in a subpopulation of neurosecretory neurons. Present findings suggest that nitric oxide (NO) is implicated in the modulation of hormone release in teleosts in a similar way to mammals.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Protein kinase C (PKC) is critical for T lymphocyte activation and proliferation, while nitric oxide synthase (NOS) may function both as an activator or inhibitor of T cell apoptosis. Both enzymatic activities were studied in T lymphoma cells in comparison to normal and activated T lymphocytes. Here we show a higher translocation of PKC in BW5147 lymphoma cells than in mitogen-stimulated T lymphocytes. Tumor cells overexpressed PKC ζ isoform, while high levels of the PKC β isotype were found in mitogen-stimulated T lymphocytes. Moreover, tumoral T cells showed high NOS activity, almost undetectable in normal or stimulated T lymphocytes. PKC and NOS inhibitors or the intracellular delivery of an anti-PKC ζ antibody diminished both NO production and proliferation in tumor cells.These results suggest that atypical PKC ζ isoform expression and its association with NOS activity regulation would participate in the multistep process leading to BW5147 cell malignant transformation. [Copyright &y& Elsevier]

Chronic ingestion of xenobiotics could be pathogenic in the gastrointestinal tract. Recently, we showed that acute low administration of a food contaminant (diquat) induced intestinal secretion involving mast cells and nitric oxide. This work aimed to determine in rats: (1) the influence of a low level (0.1 mg/kg/day per os) chronic ingestion of diquat on gastrointestinal immune cells, and (2) the participation of nitric oxide synthases (NOS) in these effects. Diquat increased both gastric and jejunal myeloperoxidase activities, tissue histamine in vitro release after stimulation by 48/80, and mast cell numbers. Diquat did not alter gastric NOS but increased intestinal inducible NOS (iNOS) activity. L-NAME prevented diquat-induced gastric and intestinal mastocytosis and gastric but not intestinal inflammation. L-NAME reduced gastric constitutive NOS (cNOS) activity and reestablished control iNOS activity. Chronic low level ingestion of diquat induces a low-grade gastric and intestinal inflammation with mastocytosis and enhancement of intestinal iNOS activity. [ABSTRACT FROM AUTHOR]