eNOS Protein Expression Levels Research Articles

Role of monoamine oxidases in the exaggerated 5-hydroxytryptamine-induced tension development of human isolated preeclamptic umbilical artery

We investigated the role(s) of monoamine oxidases (MAOs) on the altered 5-hydroxytryptamine (5-HT, serotonin)-induced tension development of the isolated umbilical artery of preeclamptic pregnancy of Chinese women. An enhanced 5-HT-induced tension development of the umbilical artery of preeclamptic pregnancy was observed when compared with that of normal pregnancy. The enhanced component of 5-HT-induced tension development was eradicated by clorgyline (a MAO-A inhibitor). Blockade of eNOS (endothelial isoform nitric oxide synthase) ( N ω-nitro- l-arginine methyl ester), 5-HT transporter (citalopram), 5-HT receptor subtypes (5HT 2B, SB 204741; 5-HT 2C, RS 102221; 5-HT 7, SB 269970), and endothelium denudation of the umbilical artery of normal pregnancy mimicked the enhanced 5-HT-induced tension development as observed in the preeclamptic tissues. In contrast, no apparent changes in 5-HT-induced tension development of the umbilical artery of preeclamptic pregnancy were observed with the same pharmacological manipulations. A decreased protein expression levels of MAO-A and eNOS (no iNOS and MAO-B expression was detected) and no change in caveolin-1 and 5-HT transporter expression were demonstrated in the umbilical artery (endothelium intact) lysate of preeclamptic pregnancy, compared to that of the umbilical artery of normal pregnancy. Thus, in the umbilical artery of preeclamptic pregnancy, a decrease of MAO-A and eNOS protein expression levels are probably associated with, or responsible for, the exaggerated 5-HT-induced tension development.

Age Related Changes from Youth to Adulthood in Rat Brain Cortex: Nitric Oxide Synthase and Mitochondrial Respiratory Function

Age related changes in brain cortex NO metabolism were investigated in mitochondria and cytosolic extracts from youth to adulthood. Decreases of 19%, 40% and 71% in NO production were observed in mitochondrial fractions from 3, 7, and 14 months old rats, respectively, as compared with 1-month-old rats. Decreased nNOS protein expression in 14 months old rats was also observed in mitochondria as compared with the nNOS protein expression in 1-month-old rats. Low levels of eNOS protein expression close to the detection limits and no iNOS protein expression were significantly detected in mitochondrial fraction for both groups of age. NO production in the cytosolic extracts also showed a marked decreasing tendency, showing higher levels than those observed in mitochondrial fractions for all groups of age. In the cytosolic extracts, however, the levels were stabilized in adult animals from 7 to 14 months. nNOS protein expression showed a similar age-pattern in cytosolic extracts for both groups of age, while the protein expression pattern for eNOS was higher expressed in adult rats (14 months) than in young animals. As well as in mitochondrial extracts iNOS protein expression was not significantly detected in cytosolic extracts at any age. RT-PCR assays indicated increased levels of nNOS mRNA in 1-month-old rats as compared with 14 months old rats, showing a similar pattern to that one observed for protein nNOS expression. A different aged pattern was observed for eNOS mRNA expression, being lower in 1-month-old rats as compared with 14 months old animals. iNOS mRNA was very low expressed in both groups of age, showing a residual iNOS mRNA that was not significantly detected. State 3 respiration rates were 78% and 85% higher when succinate and malate-glutamate were used as substrates, respectively, in 14 months rats as compared with 1-month-old rats. No changes were observed in state 4 respiration rates. These results could indicate 1 that nNOS and eNOS mRNA and protein expression can be age-dependent, and confirmed the nNOS origin for the mitochondrial NOS. During rat growth, the respiratory function seems to be modulated by NO produced by the different NOS enzymes: nNOS, eNOS and mtNOS present in the cytosol and in the mitochondria.

Hindlimb claudication reflects impaired nitric oxide-dependent revascularization after ischemia

Although vascular remodeling is important in preventing tissue damage and restoring muscle function, there is no evidence of a relationship between vascular remodeling and muscle function after peripheral vascular occlusion. Nitric oxide (NO) has been implicated in the process of vascular remodeling in hindlimb ischemia. Thus, development of alterations in hindlimb gait after ischemia may be associated with impaired nitric oxide-dependent, vascular blood flow recovery. We evaluated hindlimb gait as an index of ischemia-induced revascularization and tested the effects of NO synthase inhibition on both hindlimb blood flow and hindlimb gait locomotion. After 14 days of ischemia, the ischemic hindlimb showed no significant differences in gait locomotion compared to the sham-operated hindlimb. However, hindlimb ischemia drastically reduced hindlimb blood flow from 46 ± 3 mL/min/100 g to 12 ± 2 mL/min/100 g which reverted to 33 ± 5 mL/min/100 g after 14 days of ischemia. eNOS mRNA expression levels at 3, 7, 14, and 28 days after initiation of ischemia, were increased by 50 ± 5%, 100 ± 10%, 140 ± 8% and 270 ± 12% respectively and eNOS protein expression levels at 7, 14, and 28 days, were increased by 28 ± 3%, 62 ± 6% and 80 ± 16% respectively. However, eNOS inhibition caused by l-NAME treatment prevented blood flow recovery and correction of abnormal gait locomotion in rats. Thus, the duration of the stride-swing phase increased and the stride length decreased. The knee joint angle decreased during flexion and extension with eNOS inhibition. In conclusion, ischemia-induced revascularization is associated with recovery of both hindlimb blood flow and normal gait locomotion. Moreover, prevention of NO synthesis, a key messenger in ischemia-induced revascularization, is associated with impairment in hindlimb locomotion. Thus, gait locomotion represents a functional model that could be used to evaluate the degree of ischemia-induced revascularization.

Impairment of the vascular relaxation and differential expression of caveolin-1 of the aorta of diabetic + db/+ db mice

In this study, we compared the endothelium-dependent and -independent relaxation of the isolated thoracic aorta of control (+ db/+ m) and diabetic (+ db/+ db) (C57BL/KsJ) mice. The gene expression (mRNA and protein) level of the muscarinic M 3 receptors, endothelial nitric oxide synthase (eNOS) and caveolin-1 of the aorta was also evaluated. Acetylcholine caused a concentration-dependent, N G-nitro- l-arginine methyl-ester (20 μM)-sensitive relaxation, with ∼ 100% relaxation at 10 μM, in + db/+ m mice. In + db/+ db mice, the acetylcholine-induced relaxation was significantly smaller (maximum relaxation: ∼ 80%). The sodium nitroprusside-mediated relaxation was slightly diminished in + db/+ db mice, compared to + db/+ m mice. However, there was no significant difference in the isoprenaline- and cromakalim-induced relaxation observed in both species. The mRNA and protein expression levels of caveolin-1 were significantly higher in the aorta of + db/+ db mice. In contrast, there was no difference in the mRNA and protein expression levels of eNOS and muscarinic M 3 receptors between these mice. Our results demonstrate that the impairment of the acetylcholine-induced, endothelium-dependent aortic relaxation observed in + db/+ db mice was probably associated with an enhanced expression of caveolin-1 mRNA and protein.

Physical training increases eNOS vascular expression and activity and reduces restenosis after balloon angioplasty or arterial stenting in rats.

The effects of dynamic exercise on restenosis after vascular injury are still unknown. The consequences of balloon dilation-induced injury on neointimal hyperplasia, vascular negative remodeling, and reendothelialization were assessed in sedentary and trained rats. Ex vivo eNOS vascular expression and activity were investigated in carotid arteries isolated from sedentary and exercised rats. The in vivo effects of eNOS inhibition by L-NMMA on vessel wall after balloon dilation were evaluated in sedentary and exercised rats. We also investigated the effects of exercise on neointimal formation in a rat stent model of vascular injury. Compared with sedentary group, the arteries isolated from trained rats showed higher levels of eNOS protein expression and activity 7 days after balloon dilation. A significant reduction of both neointimal hyperplasia and negative remodeling was observed 14 days after balloon injury in trained compared with sedentary rats. Moreover, we demonstrated that exercise training produced accelerated reendothelialization of the balloon injured arterial segments compared with sedentary. L-NMMA administration eliminated the benefits of physical training on vessel wall after balloon dilation. Finally, a decrease of neointimal hyperplasia as well as of platelet aggregation was observed after stent deployment in trained rats compared with sedentary. In conclusion, physical exercise could favorably affect restenosis after balloon angioplasty and stenting. Increase in eNOS expression and activity might contribute to the potential beneficial effects of exercise on the vessel wall after vascular injury.