Effect of chronic lithium administration on endothelium-dependent relaxation of rat mesenteric bed: role of nitric oxide

2007 ◽  
Vol 85 (10) ◽  
pp. 1038-1046 ◽  
Author(s):  
Banafsheh Afsharimani ◽  
Leila Moezi ◽  
Hamed Sadeghipour ◽  
Bahareh Rahimzadeh-Rofouyi ◽  
Maliheh Nobakht ◽  
...  

The mechanism of action of lithium, an effective treatment for bipolar disease, is still unknown. In this study, the mesenteric vascular beds of control rats and rats that were chronically treated with lithium were prepared by the McGregor method, and the mesenteric vascular bed vasorelaxation responses were examined. NADPH-diaphorase histochemistry was used to determine the activity of NOS (nitric oxide synthase) in mesenteric vascular beds. We demonstrated that ACh-induced vasorelaxation increased in the mesenteric vascular bed of rats treated with lithium. Acute Nο-nitro-l-arginine methyl ester (l-NAME) administration in the medium blocked ACh-induced vasorelaxation in the control group more effectively than in lithium-treated rats, while the vasorelaxant response to sodium nitroprusside, a NO donor, was not different between lithium-treated and control groups. Acute aminoguanidine administration blocked ACh-induced vasorelaxation of lithium-treated rats, but had no effect in the control rats. Furthermore, NOS activity, determined by NADPH-diaphorase staining, was significantly greater in the mesenteric vascular beds from chronic lithium-treated rats than in those from control rats. These data suggest that the enhanced ACh-induced endothelium-derived vasorelaxation in rat mesenteric bed from chronic lithium-treated rats might be associated with increased NOS activity, likely via iNOS. Simultaneous acute l-NAME and indomethacin administration suggests the possible upregulation of EDHF (endothelium-derived hyperpolarizing factor) in lithium-treated rats.

2005 ◽  
Vol 289 (3) ◽  
pp. R776-R783 ◽  
Author(s):  
Emilia M. Sanhueza ◽  
Raquel A. Riquelme ◽  
Emilio A. Herrera ◽  
Dino A. Giussani ◽  
Carlos E. Blanco ◽  
...  

The fetal llama responds to hypoxemia, with a marked peripheral vasoconstriction but, unlike the sheep, with little or no increase in cerebral blood flow. We tested the hypothesis that the role of nitric oxide (NO) may be increased during hypoxemia in this species, to counterbalance a strong vasoconstrictor effect. Ten fetal llamas were operated under general anesthesia. Mean arterial pressure (MAP), heart rate, cardiac output, total vascular resistance, blood flows, and vascular resistances in cerebral, carotid and femoral vascular beds were determined. Two groups were studied, one with nitric oxide synthase (NOS) blocker NG-nitro-l-arginine methyl ester (l-NAME), and the other with 0.9% NaCl (control group), during normoxemia, hypoxemia, and recovery. During normoxemia, l-NAME produced an increase in fetal MAP and a rapid bradycardia. Cerebral, carotid, and femoral vascular resistance increased and blood flow decreased to carotid and femoral beds, while cerebral blood flow did not change significantly. However, during hypoxemia cerebral and carotid vascular resistance fell by 44% from its value in normoxemia after l-NAME, although femoral vascular resistance progressively increased and remained high during recovery. We conclude that in the llama fetus: 1) NO has an important role in maintaining a vasodilator tone during both normoxemia and hypoxemia in cerebral and femoral vascular beds and 2) during hypoxemia, NOS blockade unmasked the action of other vasodilator agents that contribute, with nitric oxide, to preserving blood flow and oxygen delivery to the tissues.


2003 ◽  
Vol 94 (6) ◽  
pp. 2534-2544 ◽  
Author(s):  
Wieslaw Kozak ◽  
Anna Kozak

Male C57BL/6J mice deficient in nitric oxide synthase (NOS) genes (knockout) and control (wild-type) mice were implanted intra-abdominally with battery-operated miniature biotelemeters (model VMFH MiniMitter, Sunriver, OR) to monitor changes in body temperature. Intravenous injection of lipopolysaccharide (LPS; 50 μg/kg) was used to trigger fever in response to systemic inflammation in mice. To induce a febrile response to localized inflammation, the mice were injected subcutaneously with pure turpentine oil (30 μl/animal) into the left hindlimb. Oral administration (gavage) of N G-monomethyl-l-arginine (l-NMMA) for 3 days (80 mg · kg−1 · day−1in corn oil) before injection of pyrogens was used to inhibit all three NOSs ( N G-monomethyl-d-arginine acetate salt and corn oil were used as control). In normal male C57BL/6J mice, l-NMMA inhibited the LPS-induced fever by ∼60%, whereas it augmented fever by ∼65% in mice injected with turpentine. Challenging the respective NOS knockout mice with LPS and with l-NMMA revealed that inducible NOS and neuronal NOS isoforms are responsible for the induction of fever to LPS, whereas endothelial NOS (eNOS) is not involved. In contrast, none of the NOS isoforms appeared to trigger fever to turpentine. Inhibition of eNOS, however, exacerbates fever in mice treated with l-NMMA and turpentine, indicating that eNOS participates in the antipyretic mechanism. These data support the hypothesis that nitric oxide is a regulator of fever. Its action differs, however, depending on the pyrogen used and the NOS isoform.


2015 ◽  
Vol 59 (2) ◽  
pp. 303-309
Author(s):  
Renli Jiang ◽  
Li Gao ◽  
Guanying Wang ◽  
Xinran Li ◽  
Yue Li ◽  
...  

Abstract Horses (n = 20) were divided into 2 groups: oligofructose (OF)-induced equine laminitis group (group OF; n = 11) which received 10 g/kg b.w. of OF dissolved in 4 L water via nasogastric intubation, and control group (NS; n = 9) which received 4 L of saline. Blood was collected at 4 h intervals over 72 h study period and analysed by ELISA, kinetic limulus amoebocyte lysate assay, and glucose-oxidase methods. The level of insulin changed significantly in horses which received OF (P < 0.01); there was a significant negative correlation between the level of adiponectin and insulin over time. The results suggested that insulin may play an important role in the development of OF-induced equine laminitis by altering the level of endothelin-1 and nitric oxide.


2000 ◽  
Vol 278 (4) ◽  
pp. H1211-H1217 ◽  
Author(s):  
Roby D. Rakhit ◽  
Richard J. Edwards ◽  
James W. Mockridge ◽  
Anwar R. Baydoun ◽  
Amanda W. Wyatt ◽  
...  

The aim of this study was to investigate the role of nitric oxide (NO) in a cellular model of early preconditioning (PC) in cultured neonatal rat ventricular myocytes. Cardiomyocytes “preconditioned” with 90 min of stimulated ischemia (SI) followed by 30 min reoxygenation in normal culture conditions were protected against subsequent 6 h of SI. PC was blocked by N G-monomethyl-l-arginine monoacetate but not by dexamethasone pretreatment. Inducible nitric oxide synthase (NOS) protein expression was not detected during PC ischemia. Pretreatment (90 min) with the NO donor S-nitroso- N-acetyl-l,l-penicillamine (SNAP) mimicked PC, resulting in significant protection. SNAP-triggered protection was completely abolished by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) but was unaffected by chelerythrine or the presence of glibenclamide and 5-hydroxydecanoate. With the use of RIA, SNAP treatment increased cGMP levels, which were blocked by ODQ. Hence, NO is implicated as a trigger in this model of early PC via activation of a constitutive NOS isoform. After exposure to SNAP, the mechanism of cardioprotection is cGMP dependent but independent of protein kinase C or ATP-sensitive K+ channels. This differs from the proposed mechanism of NO-induced cardioprotection in late PC.


1999 ◽  
Vol 160 (2) ◽  
pp. 275-283 ◽  
Author(s):  
A Gobbetti ◽  
C Boiti ◽  
C Canali ◽  
M Zerani

We examined the presence and the regulation of nitric oxide (NO) synthase (NOS) using in vitro cultured corpora lutea (CL) obtained from rabbits at days 4 and 9 of pseudopregnancy. The role of NO and NOS on steroidogenesis was also investigated using the same CL preparations after short-term incubations (30 min and 2 h) with the NO donor, sodium nitroprusside (NP), the NOS inhibitor, Nomega-nitro-l-arginine methyl ester (l-NAME) and prostaglandin (PG) F-2alpha. The basal NOS activity was greater in CL at day 4 than at day 9, and was also differently modulated by PGF-2alpha, depending on the age of the CL. The addition of PGF-2alpha to day 4 CL had no effect, but PGF-2alpha on day 9 caused a threefold increase in NOS activity. NP caused a two- to fivefold decrease in release of progesterone from CL of both ages, and this inhibitory effect on steroidogenesis was reversed by l-NAME. All treatments failed to modify basal androgens and 17beta-oestradiol was not detectable in either control or treated CL. These results suggest that NO is effectively involved in the regulation process of steroidogenesis, independently of 17beta-oestradiol. PGF-2alpha had no effect on day 4, but induced luteolysis on day 9, by reducing progesterone (P</=0. 01) to about 18% of control. The luteolytic action of PGF-2alpha was completely reversed by co-incubation with l-NAME, thus supporting the hypothesis that luteolysis is mediated by NO. The addition of NP or l-NAME did not modify the in vitro release of PGF-2alpha. We hypothesised that PGF-2alpha upregulates NOS activity and, consequently, the production of NO, which acutely inhibits progesterone release from day 9 CL of pseudopregnant rabbits.


1997 ◽  
Vol 82 (1) ◽  
pp. 359-363 ◽  
Author(s):  
Thomas W. Balon ◽  
Jerry L. Nadler ◽  

Balon, Thomas W., and Jerry L. Nadler. Evidence that nitric oxide increases glucose transport in skeletal muscle. J. Appl. Physiol. 82(1): 359–363, 1997.—Nitric oxide synthase (NOS) is expressed in skeletal muscle. However, the role of nitric oxide (NO) in glucose transport in this tissue remains unclear. To determine the role of NO in modulating glucose transport, 2-deoxyglucose (2-DG) transport was measured in rat extensor digitorum longus (EDL) muscles that were exposed to either a maximally stimulating concentration of insulin or to an electrical stimulation protocol, in the presence of N G-monomethyl-l-arginine, a NOS inhibitor. In addition, EDL preparations were exposed to sodium nitroprusside (SNP), an NO donor, in the presence of submaximal and maximally stimulating concentrations of insulin. NOS inhibition reduced both basal and exercise-enhanced 2-DG transport but had no effect on insulin-stimulated 2-DG transport. Furthermore, SNP increased 2-DG transport in a dose-responsive manner. The effects of SNP and insulin on 2-DG transport were additive when insulin was present in physiological but not in pharmacological concentrations. Chronic treadmill training increased protein expression of both type I and type III NOS in soleus muscle homogenates. Our results suggest that NO may be a potential mediator of exercise-induced glucose transport.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jéssica A. Troiano ◽  
Simone R. Potje ◽  
Murilo E. Graton ◽  
Emily T. Gonçalves ◽  
Rita C. Tostes ◽  
...  

We have investigated the role caveolae/caveolin-1 (Cav-1) plays in endothelial nitric oxide synthase (eNOS) activation and how it impacts pregnancy-induced decreased vascular reactivity in normotensive (Wistar rats) and spontaneously hypertensive rats (SHR). Wistar rats and SHR were divided into non-pregnant (NP) and pregnant (P). Nitrite levels were assessed by the Griess method in the aorta and mesenteric vascular bed. In functional studies, arteries were incubated with methyl-β-cyclodextrin (dextrin, 10mmol/L), which disrupts caveolae by depleting cholesterol, and concentration-response curves to phenylephrine (PE) and acetylcholine (ACh) were constructed. Electronic microscopy was used to determine endothelial caveolae density in the aorta and resistance mesenteric artery in the presence of vehicle or dextrin (10mmol/L). Western blot was performed to evaluate Cav-1, p-Cav-1, calmodulin (CaM), and heat shock protein 90 (Hsp90) expression. Cav-1/eNOS interaction in the aorta and mesenteric vascular bed was assessed by co-immunoprecipitation. Nitric oxide (NO) generation was greater in arteries from P groups compared to NP groups. Dextrin did not change vascular responses in the aorta from P groups or the number of caveolae in P groups compared to NP groups. Compared to NP Wistar rats, NP SHR showed smaller number of caveolae and reduced Cav-1 expression. Pregnancy did not alter Cav-1, CaM, or Hsp90 expression in the aorta or mesenteric vascular bed from Wistar rats or SHR. These results suggest that pregnancy does not alter expression of the main eNOS regulatory proteins, but it decreases Cav-1/eNOS interaction. Reduced Cav-1/eNOS interaction in the aorta and mesenteric vascular bed seems to be an important mechanism to increase eNOS activity and nitric oxide production in pregnant normotensive and hypertensive rats.


2005 ◽  
Vol 514 (2-3) ◽  
pp. 183-189 ◽  
Author(s):  
Amir Ali Borhani ◽  
Golbahar Houshmand ◽  
Morteza Samini ◽  
Khodadad Namiranian ◽  
Amir Reza Hajrasouliha ◽  
...  

2005 ◽  
Vol 114 (2) ◽  
pp. 122-126 ◽  
Author(s):  
Turgut Karlidaǧ ◽  
Erol Keles ◽  
Nevin İlhan ◽  
Sinasi Yakclin ◽  
İrfan Kaygusuz ◽  
...  

The aim of this study was to investigate the role of nitric oxide (NO), free oxygen radicals, and scavenging enzymes in the development of nasal polyp (NP) disease. This study included 41 patients who underwent endoscopic surgery because of NPs. Control specimens were taken from the inferior turbinate of 32 patients who underwent septoplasty. The levels of malondialdehyde (MDA), NO, and superoxide dismutase (SOD) were measured in intraoperative specimens of polyp tissue and turbinate mucosa. The levels of tissue NO were 191.06 ± 26.62 μmol/mg of protein in patients with NPs and 145.30 ± 19.19 μmol/mg of protein (p < .001) in the control group. The levels of MDA in the study and control groups were 12.47 ± 2.12 nmol/mg and 8.83 ± 1.08 nmol/mg (p < .01), respectively. The levels of SOD in the study and control groups were 50.77 ± 14.74 U/mg and 77.93 ± 15.31 U/mg (p < .001), respectively. It was determined that the levels of MDA in plasma and erythrocytes were higher in the patients with NPs than in the control group (p < .05). The levels of NO in plasma and erythrocytes in both groups were similar. The levels of SOD in plasma and erythrocytes were lower in patients with NPs than in the control group (p > .05). Increases in the levels of tissue MDA and NO and decreases in scavenging enzymes in patients with NPs as compared to control groups may indicate the presence of free radical damage in patients with nasal NPs. New studies are needed to clarify the efficacy of using antioxidants in the treatment of NPs.


2004 ◽  
Vol 287 (3) ◽  
pp. G527-G532 ◽  
Author(s):  
Maria P. Guarino ◽  
Nina C. Correia ◽  
W. Wayne Lautt ◽  
M. Paula Macedo

The hepatic parasympathetic nerves and hepatic nitric oxide synthase (NOS) are involved in the secretion of a hepatic insulin sensitizing substance (HISS), which mediates peripheral insulin sensitivity. We tested whether binding of ACh to hepatic muscarinic receptors is an upstream event to the synthesis of nitric oxide (NO), which, along with the activation of hepatic guanylate cyclase (GC), permits HISS release. Male Wistar rats (8–9 wk) were anesthetized with pentobarbital sodium (65 mg/kg). Insulin sensitivity was assessed using a euglycemic clamp [the rapid insulin sensitivity test (RIST)]. HISS inhibition was induced by antagonism of muscarinic receptors (atropine, 3 mg/kg iv) or by blockade of NOS [ NG-nitro-l-arginine methyl ester (l-NAME), 1 mg/kg intraportally (ipv)]. After the blockade, HISS action was tentatively restored using a NO donor [3-morpholynosydnonimine (SIN-1), 5–10 mg/kg ipv] or ACh (2.5–5 μg·kg−1·min−1 ipv). SIN-1 (10 mg/kg) reversed the inhibition caused by atropine (RIST postatropine 137.7 ± 8.3 mg glucose/kg; reversed to 288.3 ± 15.5 mg glucose/kg, n = 6) and by l-NAME (RIST post-l-NAME 152.2 ± 21.3 mg glucose/kg; reversed to 321.7 ± 44.7 mg glucose/kg, n = 5). ACh did not reverse HISS inhibition induced by l-NAME. The role of GC in HISS release was assessed using 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 5 nmol/kg ipv), a GC inhibitor that decreased HISS action (control RIST 237.6 ± 18.6 mg glucose/kg; RIST post-ODQ 111.7 ± 6.2 mg glucose/kg, n = 5). We propose that hepatic parasympathetic nerves release ACh, leading to hepatic NO synthesis, which activates GC, triggering HISS action.


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