Monoamine oxidase activity in tissues of spontaneously hypertensive rats

Lai, F.M.; Spector, Sidney A.

doi:10.1007/bf01915347

Cited by 5 publications

(2 citation statements)

References 4 publications

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“…Both isoforms of MAO, MAO‐A and MAO‐B, have been demonstrated in cerebral microvessels in humans (Kalaria and Harik, 1987; Youdim and Finberg, 1991). As reported earlier, an augmented expression of MAO‐A, but not of MAO‐B, was detected in cerebral arteries of SHR (Lai and Spector, 1978; Guffroy and Strolin Benedetti, 1984). Given the fact that 5‐HT is metabolized by MAOs, and H 2 O 2 is generated (Sagin et al ., 2004), it is tempting to suggest that the enhanced MAO‐A expression increased 5‐HT metabolism and a higher H 2 O 2 level was generated in SHR.…”

Section: Discussionsupporting

confidence: 83%

Mitochondrial monoamine oxidase‐A‐mediated hydrogen peroxide generation enhances 5‐hydroxytryptamine‐induced contraction of rat basilar artery

Poon

Seto

et al. 2010

British J Pharmacology

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BACKGROUND AND PURPOSE We evaluated the role(s) of monoamine oxidase (MAO)‐mediated H2O2 generation on 5‐hydroxytryptamine (5‐HT)‐induced tension development of isolated basilar artery of spontaneously hypertensive rats (SHR) and normotensive Wistar‐Kyoto (WKY) rats. EXPERIMENTAL APPROACH Basilar artery (endothelium‐denuded) was isolated for tension measurement and Western blots. Enzymically dissociated single myocytes from basilar arteries were used for patch‐clamp electrophysiological and confocal microscopic studies. KEY RESULTS Under resting tension, 5‐HT elicited a concentration‐dependent tension development with a greater sensitivity (with unchanged maximum tension development) in SHR compared with WKY (EC50: 28.4 ± 4.1 nM vs. 98.2 ± 9.4 nM). The exaggerated component of 5‐HT‐induced tension development in SHR was eradicated by polyethylene glycol‐catalase, clorgyline and citalopram whereas exogenously applied H2O2 enhanced the 5‐HT‐elicited tension development in WKY. A greater protein expression of MAO‐A was detected in basilar arteries from SHR than in those from WKY. In single myocytes and the entire basilar artery, 5‐HT generated (clorgyline‐sensitive) a greater amount of H2O2 in SHR compared with WKY. Whole‐cell iberiotoxin‐sensitive Ca2+‐activated K+ (BKCa) amplitude measured in myocytes of SHR was approximately threefold greater than that in WKY (at +60 mV: 7.61 ± 0.89 pA·pF−1 vs. 2.61 ± 0.66 pA·pF−1). In SHR myocytes, 5‐HT caused a greater inhibition (clorgyline‐, polyethylene glycol‐catalase‐ and reduced glutathione‐sensitive) of BKCa amplitude than in those from WKY. CONCLUSIONS AND IMPLICATIONS 5‐HT caused an increased generation of mitochondrial H2O2 via MAO‐A‐mediated 5‐HT metabolism, which caused a greater inhibition of BKCa gating in basilar artery myocytes, leading to exaggerated basilar artery tension development in SHR.

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Section: Discussionsupporting

confidence: 83%

Mitochondrial monoamine oxidase‐A‐mediated hydrogen peroxide generation enhances 5‐hydroxytryptamine‐induced contraction of rat basilar artery

Poon

Seto

et al. 2010

British J Pharmacology

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“…Yasuhara and colleagues observed that MAO activities were significantly higher in the brain stem, the medulla oblongata and pons of the SHR than those in WKY at 7 weeks of age . Yet, Lai and et al reported that the activity of MAO in the brain and peripheral vasculature was essentially the same in both SHR and normotensive rats . Guffroy and colleagues claimed no difference in MAO-A, MAO-B in brain between SHR and WKY, while MAO-A higher in SHR than in WKY in the liver, heart, aorta and the femoral arteries .…”

Section: Discussionsupporting

confidence: 42%

Quantitative Proteome of Medulla Oblongata in Spontaneously Hypertensive Rats

et al. 2012

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We performed an extensive quantitative proteomic analysis on the pooled medulla sample of the 11-week-old spontaneously hypertensive rats (SHR) compared to age-matched normotensive Wistar rats, using iTRAQ technology coupled with nano two-dimentional liquid chromatography followed by high resolution mass spectrometric abundance indexes techniques. Many differentially expressed proteins identified were involved in energy metabolism, such as mitochondrial part, pyruvate dehydrogenase complex, and respiratory chain. These proteins were included in citrate cycle (TCA cycle), pyruvate metabolism and oxidative phosphorylation. The proteomic analysis and subsequent Western blotting on two independent cohorts of animials indicated that the dysregulation of energy metabolism existed in the medulla of the SHR rats. The differentially expressed proteins in the dysregulation of energy metabolism in the medulla of SHR rats included down-regulated ATP6V1D, ATP6VOA1, ATP5L, DLD proteins and up-regulated AK1 protein. MAO-A protein also exhibited decreased regulation, as well as the other 3 above-mentioned energy-relative proteins (ATP6V1D, ATP5L and DLD proteins) belonging to the heterocycle metabolic process. A receiver operating characteristic curve (ROC) analysis on 4 of the differentially expressed proteins respectively resulted in an area under the receiver operating characteristic curve (AUC) of 0.95, 0.90, 0.92, and 0.81 for differentiating the SHR rats from the normotensive rats. This dysfunction in energy metabolism localizes to the medulla, the lower part of brain stem, and is, therefore, likely to contribute to the development, as well as to pathophysiological complications of hypertension.

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Monoamine oxidase and semicarbazide-sensitive amine oxidase in spontaneously hypertensive and in normotensive control rats

Guffroy¹,

Benedetti²

1984

Life Sciences

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Monoamine oxidase activity in tissues of spontaneously hypertensive rats

Cited by 5 publications

References 4 publications

Mitochondrial monoamine oxidase‐A‐mediated hydrogen peroxide generation enhances 5‐hydroxytryptamine‐induced contraction of rat basilar artery

Mitochondrial monoamine oxidase‐A‐mediated hydrogen peroxide generation enhances 5‐hydroxytryptamine‐induced contraction of rat basilar artery

Quantitative Proteome of Medulla Oblongata in Spontaneously Hypertensive Rats

Monoamine oxidase and semicarbazide-sensitive amine oxidase in spontaneously hypertensive and in normotensive control rats

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