Inhibition of iNOS augments cutaneous endothelial NO-dependent vasodilation in prehypertensive non-Hispanic Whites and in non-Hispanic Blacks.

We tested the hypothesis that inducible nitric oxide synthase (iNOS) contributes to reduced nitric oxide (NO)-dependent vasodilation in non-Hispanic Blacks and prehypertensive non-Hispanic Whites. Twenty Black and twenty White participants (10 normotensive, 10 prehypertensive per group; n = 40 total) participated in this study. Participants were instrumented with two microdialysis fibers, and each site was randomized as control (lactated Ringer) or iNOS inhibition (0.1 mM 1400W). Laser-Doppler flow probes and local heaters were used to measure skin blood flow and heat the skin to induce vasodilation, respectively. Each site was heated from 33°C to 39°C (rate: 0.1°C/s). Once a plateau was established, 20 mM nitro-l-arginine methyl ester (l-NAME), a nonspecific NOS inhibitor, was infused at each site to quantify NO-dependent vasodilation. At control sites, %NO-dependent vasodilation was reduced in prehypertensive Whites (47 ± 10%NO) and in both normotensive and prehypertensive Blacks (39 ± 9%NO and 28 ± 5%NO, respectively) relative to normotensive Whites (73 ± 8%NO; P < 0.0001 for all comparisons). Compared with respective control sites, iNOS inhibition increased NO-dependent vasodilation in prehypertensive Whites (68 ± 8%NO) and in both normotensive and prehypertensive Blacks (78 ± 8%NO and 55 ± 6%NO, respectively; P < 0.0001 for all comparisons). We failed to find an effect for normotensive Whites (77 ± 7%NO). After iNOS inhibition, %NO-dependent vasodilation was similar between normotensive Whites, prehypertensive Whites, and normotensive Blacks. Inhibition of iNOS increased NO-dependent vasodilation to a lesser extent in prehypertensive Blacks. These data suggest that iNOS contributes to reduced NO-dependent vasodilation in prehypertension and in Black participants.NEW & NOTEWORTHY Inducible nitric oxide synthase (iNOS) is typically upregulated in conditions of increased oxidative stress and may have detrimental effects on the vasculature. Endothelial nitric oxide (NO), which is cardioprotective, is reduced in prehypertensive non-Hispanic Whites and in non-Hispanic Blacks. We found that inhibition of iNOS can increase endothelial NO-dependent vasodilation in prehypertensive White participants and in both normotensive and prehypertensive Black participants.Inducible nitric oxide (NO) synthase (iNOS) can be upregulated under conditions of increased oxidative stress and may have detrimental effects on the vasculature. Endothelial NO, which is cardioprotective, is reduced in prehypertensive non-Hispanic Whites and in non-Hispanic Blacks. We found that inhibition of iNOS can increase endothelial NO-dependent vasodilation in prehypertensive White participants and in both normotensive and prehypertensive Black participants.

Protein disulfide isomerase-mediated S-nitrosylation facilitates surface expression of P2X7 receptor following status epilepticus.

BACKGROUND: P2X7 receptor (P2X7R) is an ATP-gated nonselective cationic channel playing important roles in a variety of physiological functions, including inflammation, and apoptotic or necrotic cell death. An extracellular domain has ten cysteine residues forming five intrasubunit disulfide bonds, which are needed for the P2X7R trafficking to the cell surface and the recognition of surface epitopes of apoptotic cells and bacteria. However, the underlying mechanisms of redox/S-nitrosylation of cysteine residues on P2X7R and its role in P2X7R-mediated post-status epilepticus (SE, a prolonged seizure activity) events remain to be answered. METHODS: Rats were given pilocarpine (380 mg/kg i.p.) to induce SE. Animals were intracerebroventricularly infused Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME, a NOS inhibitor) 3 days before SE, or protein disulfide isomerase (PDI) siRNA 1 day after SE using an osmotic pump. Thereafter, we performed Western blot, co-immunoprecipitation, membrane fraction, measurement of S-nitrosylated (SNO)-thiol and total thiol, Fluoro-Jade B staining, immunohistochemistry, and TUNEL staining. RESULTS: SE increased S-nitrosylation ratio of P2X7R and the PDI-P2X7R bindings, which were abolished by L-NAME and PDI knockdown. In addition, both L-NAME and PDI siRNA attenuated SE-induced microglial activation and astroglial apoptosis. L-NAME and PDI siRNA also ameliorated the increased P2X7R surface expression induced by SE. CONCLUSIONS: These findings suggest that PDI-mediated redox/S-nitrosylation may facilitate the trafficking of P2X7R, which promotes microglial activation and astroglial apoptosis following SE. Therefore, our findings suggest that PDI-mediated regulations of dynamic redox status and S-nitrosylation of P2X7R may be a critical mechanism in the neuroinflammation and astroglial death following SE.

CRIP1 expression in monocytes related to hypertension.

Hypertension is a complex and multifactorial disorder caused by lifestyle and environmental factors, inflammation and disease-related genetic factors and is a risk factor for stroke, ischemic heart disease and renal failure. Although circulating monocytes and tissue macrophages contribute to the pathogenesis of hypertension, the underlying mechanisms are poorly understood. Cysteine rich protein 1 (CRIP1) is highly expressed in immune cells, and CRIP1 mRNA expression in monocytes associates with blood pressure (BP) and is up-regulated by proinflammatory modulation suggesting a link between CRIP1 and BP regulation through the immune system. To address this functional link, we studied CRIP1 expression in immune cells in relation to BP using a human cohort study and hypertensive mouse models. CRIP1 expression in splenic monocytes/macrophages and in circulating monocytes was significantly affected by angiotensin II (Ang II) in a BP-elevating dose (2 mg/kg/day). In the human cohort study, monocytic CRIP1 expression levels were associated with elevated BP, whereas upon differentiation of monocytes to macrophages this association along with the CRIP1 expression level was diminished. In conclusion, CRIP1-positive circulating and splenic monocytes seem to play an important role in hypertension related inflammatory processes through endogenous hormones such as Ang II. These findings suggest that CRIP1 may affect the interaction between the immune system, in particular monocytes, and the pathogenesis of hypertension.

L-NAME Administration Enhances Diabetic Kidney Disease Development in an STZ/NAD Rat Model.

One of the most important risk factors for developing chronic kidney disease (CKD) is diabetes. To assess the safety and efficacy of potential drug candidates, reliable animal models that mimic human diseases are crucial. However, a suitable model of diabetic kidney disease (DKD) is currently not available. The aim of this study is to develop a rat model of DKD by combining streptozotocin and nicotinamide (STZ/NAD) with oral N(ω)-Nitro-L-Arginine Methyl Ester (L-NAME) administration. Diabetes was induced in male Wistar rats by intravenous injection of 65 mg/kg STZ, 15 min after intraperitoneal injection of 230 mg/kg NAD. Rats were assigned to different groups receiving L-NAME (100 mg/kg/day) (STZ/NAD/L-NAME) or vehicle (STZ/NAD) for a period of 9 or 12 weeks by daily oral gavage. All rats developed hyperglycemia. Hyperfiltration was observed at the start of the study, whereas increased serum creatinine, albumin-to-creatinine ratio, and evolving hypofiltration were detected at the end of the study. Daily L-NAME administration caused a rapid rise in blood pressure. Histopathological evaluation revealed heterogeneous renal injury patterns, which were most severe in the STZ/NAD/L-NAME rats. L-NAME-induced NO-deficiency in STZ/NAD-induced diabetic rats leads to multiple characteristic features of human DKD and may represent a novel rat model of DKD.

l-Arginine Inhibits Apoptosis of Ovine Intestinal Epithelial Cells through the l-Arginine-Nitric Oxide Pathway.

BACKGROUND: In nonruminants, many of the biological roles of l-arginine (Arg) at the intestinal level are mediated through the Arg-nitric oxide (Arg-NO) pathway. Whether the Arg-NO pathway is involved in controlling the immune response and viability in ovine intestinal epithelial cells (IOECs) is unclear. OBJECTIVES: The current study aimed to examine the role of the Arg-NO pathway in apoptosis, antioxidant capacity, and mitochondrial function of IOECs. METHODS: The IOECs were incubated in Arg-free DMEM supplemented with 150 µM Arg (CON) or 300 µM Arg (ARG) alone or with 350 µM Nw-nitro-l-arginine methyl ester hydrochloride (l-NAME) (CON + NAME, ARG + NAME) for 24 h. The reactive oxygen species (ROS) concentration, antioxidant capacity, and cell apoptotic percentage were determined. RESULTS: Arg supplementation decreased (P < 0.05) the ROS concentration (38.9% and 22.7%) and apoptotic cell percentage (57.2% and 54.8%) relative to the CON and CON + NAME groups, respectively. Relative to the CON and ARG treatments, the l-NAME administration decreased (P < 0.05) the mRNA abundance of superoxide dismutase 2 (32% and 21.3%, respectively) and epithelial NO synthase (36% and 29.1%, respectively). Arg supplementation decreased (P < 0.05) the protein abundance of apoptosis antigen 1 (FAS) (52.0% and 43.9%) but increased (P < 0.05) those of nuclear respiratory factor 1 (31.3% and 22.9%) and inducible NO synthase (35.2% and 41.8%) relative to the CON and CON + NAME groups, respectively. CONCLUSIONS: The inhibition of apoptosis in IOECs due to the increased supply of Arg is associated with the mitochondria- and FAS-dependent pathways through the activity of the Arg-NO pathway. The findings help elucidate the role of the Arg-NO pathway in IOEC growth and apoptosis.

Participation of the opioid receptor - nitric oxide - cGMP - K+ channel pathway in the peripheral antinociceptive effect of nalbuphine and buprenorphine in rats.

The aim of this study was to examine if the peripheral antinociceptive effects of the opioid agonist/antagonist nalbuphine and buprenorphine involve the sequential participation of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) synthesis followed by K+ channel opening in the formalin test. Wistar rats (180-220 g) were injected in the dorsal surface of the right hind paw with formalin (1%). Rats received a subcutaneous (s.c.) injection into the dorsal surface of the paw of vehicles or increasing doses of nalbuphine (50-200 µg/paw) or buprenorphine (1-5 µg/paw) 20 min before formalin injection into the paw. Nalbuphine antinociception was reversed by the s.c. injection into the paw of the inhibitor of NO synthesis (NG-nitro-l-arginine methyl ester (L-NAME)), by the inhibitor of guanylyl cyclase (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ)), by the Kir6.1-2, ATP-sensitive K+ channel inhibitors (glibenclamide and glipizide), by the KCa2.1-3, small conductance Ca2+-activated K+ channel blocker (apamin), by the KCa1.1, large conductance Ca2+-activated K+ channel blocker (charybdotoxin), and by the KV, voltage-dependent K+ channel inhibitors (4-aminopyridine (4-AP) and tetraethylammonium chloride (TEA)). The antinociceptive effect produced by buprenorphine was blocked by the s.c. injection of 4-AP and TEA but not by L-NAME, ODQ, glibenclamide, glipizide, apamin, or charybdotoxin. The present results provide evidence for differences in peripheral mechanisms of action between these opioid drugs.

Role of Nitric Oxide in the Change of 5-Hydroxytryptamine Synthesis in the Intestine by a Consecutive Administration of Methotrexate to Rats.

This study aimed to investigate whether the consecutive administration of methotrexate affects 5-hydroxytryptamine (5-HT) synthesis in the rat small intestine. Rats received methotrexate at a dose of 12.5 mg/kg intraperitoneally on 4 consecutive days. NG-nitro-L-arginine methyl ester (L-NAME) was given subcutaneously to inhibit nitric oxide (NO) synthase. Methotrexate moderately altered 5-HT synthesis, whereas the combined administration of methotrexate and L-NAME significantly changed 5-HT synthesis in the rat ileal tissue. These results suggest that endogenous NO has an antagonistic role in the induction of 5-HT synthesis in rats following the consecutive administration of methotrexate.

Renin angiotensin system molecules and nitric oxide local interactions in the adrenal gland of Trypanosoma cruzi infected rats.

Chagas disease (CD) is a tropical zoonosis caused by the protozoan Trypanosoma cruzi. Severe autonomic dysfunction like reduced cardiac catecholamine-containing or acetylcholinesterase-positive innervation have been reported in CD. Renin-angiotensin system (RAS) seems to participate in the regulation of adrenal catecholamine secretion by adrenal medullary chromaffin cells, which might be dependent of nitric oxide (NO) pathways. To investigate the levels of RAS components in the adrenal gland during the acute infection with Y strain T. cruzi and in response to acute administration of an inhibitor of the enzyme NO synthase, L-NAME. Male Holtzman rats were inoculated intraperitoneally with Y strain T. cruzi and received L-NAME or tap water from one day before the infection until 13 or 17 days post-inoculation (dpi). The concentration of RAS molecules in the adrenal tissue was evaluated by ELISA immunoassay. Angiotensin converting enzyme 1 (ACE1) levels were significantly lower at 17 dpi when compared to 13 dpi. No significant differences were found compared with baseline, and no changes were detected in adrenal tissue levels of angiotensin converting enzyme 2 (ACE2), angiotensin II, or angiotensin-(1-7). Moreover, the treatment with L-NAME did not influence the levels of RAS components in adrenal tissue during the course of T. cruzi infection. We provided the first evidence that levels of RAS molecules change in the adrenal gland during acute phase of T. cruzi infection. Future studies are necessary to fully address the role of NO in RAS-associated adrenal gland function in CD.

Resveratrol promotes trophoblast invasion in pre-eclampsia by inducing epithelial-mesenchymal transition.

Impairment spiral arteries remodelling was considered to be the underlying cause of pathogenesis of pre-eclampsia (PE). Resveratrol (RE) was reported that it could modulate cellar phenotype to ameliorate diverse human diseases. However, the biological function of RE in PE remains poorly understood. In this report, we investigated the effect of RE on trophoblast phenotype both in vivo and in vitro. We conducted MTT and transwell assays to explore cell proliferation and invasion events in HTR-8/SVneo. In mice model, the clinical characteristics of PE were established through the injection of NG-nitro-l-arginine methyl ester (L-NAME). Furthermore, related experiments were performed to detect cellar phenotype-associated signalling pathway, including epithelial-mesenchymal transition (EMT) and Wnt/ß-catenin. Cell assays indicated that RE could increase trophoblasts migration and invasion. In addition, hypertension and proteinuria were markedly ameliorated by RE compared with the controls in PE mice model. Moreover, treatment by RE in trophoblasts or in PE model, we found that RE activated EMT progress through the regulation of E-cadherin, ß-catenin, N-cadherin, vimentin expression, and further altered the WNT-related gene expression, including WNT1, WNT3 and WNT5B. Our findings demonstrated that RE might stimulate the invasive capability of human trophoblasts by promoting EMT and mediating the Wnt/ß-catenin pathway in PE.

The contribution of cross-talk between the cell-surface proteins CD36 and CD47-TSP-1 in osteoclast formation and function.

Antibody-mediated blockade of cluster of differentiation 47 (CD47)-thrombospondin-1 (TSP-1) interactions blocks osteoclast formation in vitro and attenuates parathyroid hormone (PTH)-induced hypercalcemia in vivo in mice. Hypercalcemia in this model reflects increased bone resorption. TSP-1 has two cell-associated binding partners, CD47 and CD36. The roles of these two molecules in mediating the effects of TSP1 in osteoclasts are unclear. Osteoclast formation was attenuated but not absent when preosteoclasts isolated from CD47-/- mice were cocultured with WT osteoblasts. Suppressing CD36 in osteoclast progenitors also attenuated osteoclast formation. The hypercalcemic response to a PTH infusion was blunted in CD47-/-/CD36-/- (double knockout (DKO)) female mice but not CD47-/- mice or CD36-/- animals, supporting a role for both CD47 and CD36 in mediating this effect. Consistent with this, DKO osteoclasts had impaired resorptive activity when analyzed in vitro Inhibition of nitric oxide (NO) signaling is known to promote osteoclastogenesis, and TSP-1 suppresses NO production and signaling. An anti-TSP-1 antibody increased NO production in osteoclasts, and the inhibitory effect of anti-TSP-1 on osteoclastogenesis was completely rescued by l-nitroarginine methyl ester (l-NAME), a competitive NO synthase inhibitor. Supportive of an important role for CD36 in mediating the pro-osteoclastogenic effects of TSP-1, engaging CD36 with a synthetic agonist, p907, suppressed NO production in anti-TSP-1-treated cultures, allowing osteoclast maturation to occur. These results establish that CD36 and CD47 both participate in mediating the actions of TSP-1 in osteoclasts and establish a physiologically relevant cross-talk in bone tissue between these two molecules.

The role of nitric oxide signaling in renoprotective effects of hydrogen sulfide against chronic kidney disease in rats: Involvement of oxidative stress, autophagy and apoptosis.

The interplay between H2 S and nitric oxide (NO) is thought to contribute to renal functions. The current study was designed to assess the role of NO in mediating the renoprotective effects of hydrogen sulfide in the 5/6 nephrectomy (5/6 Nx) animal model. Forty rats were randomly assigned to 5 experimental groups: (a) Sham; (b) 5/6 Nx; (c) 5/6Nx+sodium hydrosulfide-a donor of H 2 S, (5/6Nx+sodium hydrosulfide [NaHS]); (d) 5/6Nx+NaHS+ L-NAME (a nonspecific nitric oxide synthase [NOS] inhibitor); (e) 5/6Nx+NaHS+aminoguanidine (a selective inhibitor of inducible NOS [iNOS]). Twelve weeks after 5/6 Nx, we assessed the expressions of iNOS and endothelial NOS (eNOS), oxidative/antioxidant status, renal fibrosis, urine N-acetyl-b-glucosaminidase (NAG) activity as the markers of kidney injury and various markers of apoptosis, inflammation, remodeling, and autophagy. NaHS treatment protected the animals against chronic kidney injury as depicted by improved oxidative/antioxidant status, reduced apoptosis, and autophagy and attenuated messenger RNA (mRNA) expression of genes associated with inflammation, remodeling, and NAG activity. Eight weeks Nω-nitro-l-arginine methyl ester ( L-NAME) administration reduced the protective effects of hydrogen sulfide. In contrast, aminoguanidine augmented the beneficial effects of hydrogen sulfide. Our finding revealed some fascinating interactions between NO and H 2 S in the kidney. Moreover, the study suggests that NO, in an isoform-dependent manner, can exert renoprotective effects in 5/6 Nx model of CKD.

Separate and combined effects of KCa and KATP channel blockade with NOS inhibition on cutaneous vasodilation and sweating in older men during heat stress.

Our objective in this study was to examine the separate and combined effects of potassium (K+) channels and nitric oxide synthase (NOS) on cutaneous vasodilation and sweating in older men during rest and exercise in the heat. In 13 habitually active men (61 ± 4 yr), cutaneous vascular conductance and local sweat rate were assessed at six dorsal forearm skin sites continuously perfused with either 1) lactated Ringer (control), 2) 10 mM NG-nitro-l-arginine methyl ester (l-NAME, NOS inhibitor), 3) 50 mM tetraethylammonium (TEA; Ca2+-activated K+ channel blocker), 4) 5 mM glybenclamide (GLY; ATP-sensitive K+ channel blocker), 5) 50 mM TEA + 10 mM l-NAME, and 6) 5 mM GLY + 10 mM l-NAME via microdialysis. Participants rested in non-heat stress (25°C) and heat stress (35°C) conditions for ∼60 min each, followed by 50 min of moderate-intensity cycling (∼55% V̇o2peak) and 30 min of recovery in the heat. During rest and exercise in the heat, l-NAME, TEA + l-NAME, and GLY + l-NAME attenuated CVC relative to control (all P ≤ 0.05), although l-NAME was not different from TEA + l-NAME or GLY + l-NAME (all P > 0.05). TEA attenuated CVC during rest, whereas GLY attenuated CVC during exercise (both P ≤ 0.05). Additionally, whereas neither l-NAME nor TEA altered sweating throughout the protocol (all P > 0.05), combined TEA + l-NAME attenuated sweating during exercise in the heat (P ≤ 0.05). We conclude that in habitually active older men blockade of KCa and KATP channels attenuates cutaneous vasodilation during rest and exercise in the heat, respectively, and these effects are NOS dependent. Furthermore, combined NOS inhibition and KCa channel blockade attenuates sweating during exercise in the heat.

The effects of extremely low-frequency pulsed electromagnetic fields on analgesia in the nitric oxide pathway.

There is growing interest in the effects of extremely low-frequency electromagnetic fields on mechanisms in biological organisms. This study's goal is to determine the role of the Nitiric Oxide (NO) pathway for thermal pain by intentionally interfering with it using a pulsed electromagnetic field generated by an extremely low-frequency alternating current (ELF-PEMF) in combination with BAY41-2272 (sGC activator), NOS inhibitor l-NAME, and NO donor l-arginine. This study included 72 adult male Wistar albino rats (mean weight of 230 ±â€¯12 g). The rats were kept at room temperature (22 ±â€¯2 °C) in a 12-h light/dark cycle and in a room with sound insulation. PEMF (50 Hz, 5 mT) were applied four times a day for 30 min and at 15-min intervals for 15 days. Analgesic effects were assessed with tail-flick and hot-plate tests. Before the tests, NO donor l-arginine (300 mg/kg), sGC activator BAY41-2272 (10 mg/kg), and NOS inhibitor l-name (40 mg/kg) were injected intraperitoneally into rats in six randomly-selected groups. The maximum analgesic effect of a 5 mT electromagnetic field was on day 7. PEMF significantly increased the analgesia effect when the functioning of the NO pathway was ensured with l-arginine, which is a NO donor, and BAY41-2271, which is the intracellular receptor and sGC activator. However, there was no difference between rats treated with PEMF and the NOS inhibitor l-NAME as compared to rats only treated with PEMF. In conclusion, PEMF generate analgesia by activating the NO pain pathway.

Effects of N-nitro L-arginine methyl ester and α-tocopherol on testicular oxidative stress caused by exposure to cigarette smoke.

Testis is a rich organ with blood vessels. For this reason, it is possible that the toxic substances of the cigarette carried in the blood change the balance between the oxidant and the antioxidant system in this organ. In this study, it was aimed to investigate the effects of N-nitro L-arginine methyl ester and α-tocopherol on testicular oxidative stress caused by exposure to cigarette smoke. 45 wistar male rats were used in the study. Five groups were formed: control, cigarette smoke, cigarette smoke + α-tocopherol, cigarette smoke + N-nitro L-arginine methyl ester and cigarette smoke + α-tocopherol + N-nitro L-arginine methyl ester. Biochemical and histological evaluations were performed to determine the damage caused by cigarette smoke. It was observed that there were structural and functional disturbances at the cellular and hormonal level in the smoking group. Biochemical evaluations showed that cellular damage was reduced in treatment groups. Histological examinations were revealed that the damage caused by cigarette smoke exposure was eliminated in treatment groups. As a result of our study, we think that oxidative damage and hormonal irregularity in the testes tissue caused by cigarette smoke exposure can be improved with α-tocopherol and N-nitro L-arginine methyl ester application.

Involvement of l-arginine-nitric oxide pathway in the antidepressant and memory promoting effects of morin in mice.

l-Arginine-nitric oxide pathway has been reported to be involved in the mediation of the psychopharmacological effects of many psychotropic drugs. Previous studies have shown that morin, a psychotropic compound isolated from mulberry leaf produces functional psychopharmacological effects indicative of antidepressant, antipsychotic, anxiolytic and nootropic properties. However, the role of l-arginine-nitric oxide pathway in the psychotropic effects of morin has not been fully investigated, hence, the need for this study. Male Swiss mice were pretreated individually or in combination with nitric oxide precursor [l-arginine (750 mg/kg, i.p.)], competitive nonselective nitric oxide synthase (NOS) inhibitor [N(G)-nitro-l-arginine methyl ester (l-NAME, i.p) (50 mg/kg)] or selective neuronal NOS inhibitor [methylene blue (3.75 mg/kg, i.p)] prior to morin (100 mg/kg, i.p.) or saline (10 mL/kg, i.p.) treatment. Psychopharmacological activities were then evaluated 30 min later using open field, Y-maze, and forced swim tests. l-Arginine significantly reversed the effects of morin on locomotion, memory and depression in mice. The reduced motor activity and enhanced memory function produced by morin were significantly attenuated by methylene blue but augmented the antimobility activity of morin in the FST. Moreover, l-NAME potentiated the psychopharmacological effects of morin in the open field and forced swim tests but reduced its memory promoting effect. Meanwhile, morin supplementation reversed the effects of l-arginine on l-NAME-treated mice in all behavioral models. The results of this study suggest that l-arginine-nitric oxide pathway might play a role in the modulation of the antidepressant and memory promoting effects of morin in mice.

Gastroprotection of Calein D against Ethanol-Induced Gastric Lesions in Mice: Role of Prostaglandins, Nitric Oxide and Sulfhydryls.

Peptic ulcers are currently treated with various drugs, all having serious side effects. The aim of this study was to evaluate the gastroprotective activity of calein D (from Calea urticifolia), a sesquiterpene lactone with a germacrane skeleton. Gastric lesions were induced in mice by administering ethanol (0.2 mL) after oral treatment with calein D at 3, 10 and 30 mg/kg, resulting in 13.15 ± 3.44%, 77.65 ± 7.38% and 95.76 ± 2.18% gastroprotection, respectively, to be compared with that of the control group. The effect found for 30 mg/kg of calein D was not reversed by pretreatment with NG-nitro-l-arginine methyl ester (l-NAME, 70 mg/kg, ip), indomethacin (10 mg/kg, sc) or N-ethylmaleimide (NEM, 10 mg/kg, sc). Hence, the mechanism of action of calein D does not involve NO, prostaglandins or sulfhydryl compounds. Calein D was more potent than carbenoxolone, the reference drug. The findings for the latter are in agreement with previous reports.

Ethyl Rosmarinate Prevents the Impairment of Vascular Function and Morphological Changes in L-NAME-Induced Hypertensive Rats.

Background and Objectives: The potent, endothelium-independent, vasorelaxant effect of ethyl rosmarinate, an ester derivative of rosmarinic acid, makes it of interest as an alternative therapeutic agent for use in hypertension. This study was designed to investigate the effect of ethyl rosmarinate on Nω-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats. Materials and Methods: L-NAME was given orally to male Wistar rats for 6 weeks to induce hypertension concurrently with treatment of ethyl rosmarinate at 5, 15, or 30 mg/kgor enalapril at 10 mg/kg Systolic blood pressure (SBP), heart rate, and body weight of all experimental groups were recorded weekly, while the vascular sensitivity and histological changes of the aorta were evaluated at the end of the experiment. Results: For all treatment groups, the data indicated that ethyl rosmarinate significantly attenuated the SBP in hypertensive rats induced by L-NAME, with no significant differences in heart rate and body weight. In addition, the response of vascular sensitivity to acetylcholine (ACh) was improved but there was no significant difference in the response to sodium nitroprusside (SNP). Furthermore, the sensitivity of the aorta to phenylephrine (PE) was significantly decreased. The thickness of the aortic wall did not differ between groups but the expression of endothelial nitric oxide synthase (eNOS) was increased in ethyl rosmarinate- and enalapril-treated groups compared with the hypertensive group. Conclusions: Ethyl rosmarinate is an interesting candidate as an alternative treatment for hypertension due to its ability to improve vascular function and to increase the expression of eNOS similar to enalapril which is a drug commonly used in hypertension.

Perillaldehyde prevents the formations of atherosclerotic plaques through recoupling endothelial nitric oxide synthase.

BACKGROUNDS: Nitric oxide (NO) produced by endothelial NO synthase (eNOS) is essential for cardiovascular homeostasis owing to its anti-inflammatory, antithrombotic, antiproliferative, and antioxidant effects. Perillaldehyde (PAH), one of the major oil components in Perilla frutescens, has anti-inflammatory effects. AIM: This study was designed to explore whether PAH prevents atherosclerosis through normalizing eNOS functions. METHODS: The model of atherosclerosis was induced by feeding rats and mice with high-fat diet or plus balloon injury. Oil red and hematoxylin-eosin (HE) stainings were used to assess the atherosclerotic plaque. RESULTS: Pretreatment of PAH for 30 minutes concentration-dependently increased tetrahydrobiopterin (BH4) levels, NO generations, and improved cell viabilities in cultured human umbilicus vessel endothelial cells (HUVEC) incubated with oxidized (OX) low-density lipoprotein (LDL), in which all protective effects of PAH were abolished by guanosinetriphosphate (GTP) cyclohydrolase 1 inhibitor 2,4-Diamino-6-hydroxypyrimidine (DAHP) or eNOS inhibitor L-NAME in those cells. In rats, high-fat diet plus balloon injury induced the formation of atherosclerotic plaque in carotid arteries. Administration of PAH or lovastatin reduced the size of atherosclerotic plaque in rats and improved the responses of aortic rings to acetylcholine isolated from rats, accompanied with increased BH4 content and NO generations. In Apoe -/- mice feeding with normal diet or high-fat diet, PAH (150 mg/kg) reduced the size of atherosclerotic plaque in aortic arteries, prevented endothelial dysfunctions, and increased both BH4 and NO generations in carotid arteries. CONCLUSION: PAH prevents the growth of atherosclerosis through increasing BH4 generation and subsequent eNOS recouping. Clinically, PAH should be considered as a new medicine to treat patients with atherosclerosis.

Effects of quercetin on heart nitric oxide metabolism in l-NAME treated rats.

This study investigated the effects of a quercetin-supplemented diet on the biochemical changes installed in the heart of NO-deficient rats in terms of oxidants production and NO bioavailability determinants. Sprague-Dawley rats were subjected to Nω-nitro-l-arginine methyl ester (l-NAME) treatment (360 mg/L l-NAME in the drinking water, 4 d) with or without supplementation with quercetin (4 g/kg diet). l-NAME administration led to increased blood pressure (BP) (30%), decreased nitric oxide synthase (NOS) activity (50%), and increases in NADPH oxidase (NOX)-dependent superoxide anion production (60%) and p47phox protein level (65%). The co-administration of quercetin prevented the increase in BP and the activation of NOX but did not modify the decrease in NOS activity caused by l-NAME. In addition, quercetin affected oxidative stress parameters as glutathione oxidation, and the activities of oxidant detoxifying enzymes superoxide dismutase, glutathione peroxidase, and catalase. Thus, quercetin administration counteracts l-NAME effects on NO bioavailability determinants in vivo, essentially through controlling NOX-mediated superoxide anion production.

Inhibition of neuronal nitric oxide synthase attenuate the hypothermic effect of ketamine-magnesium sulfate combination in rats.

Ketamine and magnesium as NMDA receptor antagonists interact synergistically to decrease body temperature in rats. The mechanism of the hypothermic effect of the ketamine-magnesium sulfate combination has not been studied until now. The aim of this study was to examine whether nitric oxide (NO) has a role in the hypothermic effect of ketamine (10 mg/kg) and the combination of ketamine (5 mg/kg) and magnesium sulfate (5 mg/kg). The body temperature was measured by insertion of a thermometer probe 5 cm into the colon of unrestrained male Wistar rats (200-250 g). N(ω)-nitro-L-arginine methyl ester (L-NAME 2.5 and 5 mg/kg) as non-selective inhibitor of nitric oxide synthase at a dose of 5 mg/kg antagonized the effect of the ketamine-magnesium sulfate combination at 60 min (p < 0.05) and 90 min (p < 0.01). Ketamine induced hypothermia was not affected by administrating of L-NAME (2.5 and 5 mg/kg). Inhibitor of inducible nitric oxide synthase N6-(1-Iminoethyl)-L-lysine hydrochloride (L-NIL 1.25 mg/kg and 2.5 mg/kg, sc) did not significantly change the hypothermic response evoked by the ketamine-magnesium sulfate combination. Inhibitor of neuronal nitric oxide synthase N-ω-Propyl-L-arginine hydrochloride (L-NPA) at a dose of 2 mg/kg antagonized the combination at 60 min when it achieved the maximum effect. The NO pathway is not involved in the hypothermic effect of ketamine. Production of NO through neuronal NO synthase, might play a role in the mechanism of the hypothermic effect of the ketamine-magnesium sulfate combination.