α1A-Adrenoceptors, but not α1B- or α1D-adrenoceptors, contribute to enhanced contractile response to phenylephrine in cooling conditions in the rat tail artery

Ishida, Hirotake; Ishikawa, Tomohisa

doi:10.1016/j.ejphar.2018.09.004

Cited by 6 publications

(3 citation statements)

References 25 publications

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“…Second, the blood in the lumen is replaced by physiological salt solution when mounted in the myography chamber, which could affect myogenic tone. Third, the experimental temperature could affect the degree of arterial contraction [28, 29]. As we collect the mesenteric artery in ice-cold solution to prevent tissue degradation, a certain degree of vasoconstriction could have occurred.…”

Section: Discussionmentioning

confidence: 99%

Automated Detection and Diameter Estimation for Mouse Mesenteric Artery Using Semantic Segmentation

et al. 2021

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Background: Pressurized myography is useful for the assessment of small artery structures and function. However, this procedure requires technical expertise for sample preparation and effort to choose an appropriate sized artery. In this study, we developed an automatic artery/vein differentiation and a size measurement system utilizing machine learning algorithms. Methods and Results: We used 654 independent mouse mesenteric artery images for model training. The model yielded an Intersection-over-Union of 0.744 ± 0.031 and a Dice coefficient of 0.881 ± 0.016. The vessel size and lumen size calculated from the predicted vessel contours demonstrated a strong linear correlation with manually determined vessel sizes (R = 0.722 ± 0.048, p < 0.001 for vessel size and R = 0.908 ± 0.027, p < 0.001 for lumen size). Last, we assessed the relation between the vessel size before and after dissection using a pressurized myography system. We observed a strong positive correlation between the wall/lumen ratio before dissection and the lumen expansion ratio (R = 0.832, p < 0.01). Using multivariate binary logistic regression, 2 models estimating whether the vessel met the size criteria (lumen size of 160–240 μm) were generated with an area under the receiver operating characteristic curve of 0.761 for the upper limit and 0.747 for the lower limit. Conclusion: The U-Net-based image analysis method could streamline the experimental approach.

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Section: Discussionmentioning

confidence: 99%

Automated Detection and Diameter Estimation for Mouse Mesenteric Artery Using Semantic Segmentation

et al. 2021

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“…Second, the blood in the lumen will be replaced by physiological salt solution when mounted in the myography chamber, which could affect myogenic tone. Third, the experimental temperature could affect the degree of arterial contraction (27,28). As we collect the mesenteric artery in ice-cold solution to prevent tissue degradation, a certain degree of vasoconstriction could have occurred.…”

Section: Discussionmentioning

confidence: 99%

Automated Detection and Diameter Estimation for Mouse Mesenteric Artery using Semantic Segmentation

Higaki

Mahmoud

Paradis

et al. 2020

Preprint

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Background: Pressurized myography is useful for the assessment of small artery structure and function, and widely used in the field of cardiovascular research. However, this procedure requires technical expertise for the sample preparation and effort to choose an appropriate size of artery. In this study we sought to develop an automatic artery-vein differentiation and size measurement system utilizing the U-Net-based machine learning algorithms. Methods and Results: We used 654 independent mesenteric artery images from 59 mice for the model training and validation. Our segmentation model yielded 0.744 ± 0.031 in IoU and 0.881 ± 0.016 in Dice coefficient with 5-fold cross validation. The vessel size and the lumen size calculated from the predicted vessel contours demonstrated a strong linear correlation with the manually determined vessel sizes (R = 0.722 ± 0.048, p<0.001 for vessel size and R = 0.908 ± 0.027, p<0.001 for lumen size). Lastly, we assessed the relation between the vessel size before and after dissection using pressurized myography system. We observed a strong positive correlation between the wall/lumen ratio before dissection and the lumen expansion ratio (R2 = 0.671, p<0.01). Using multivariate binary logistic regression, two models estimating whether the vessel met the size criteria (lumen size of 160 to 240 μm) were generated with area under the ROC curve of 0.761 for the upper limit and 0.747 for the lower limit. Conclusion: Our novel image analysis method with U-Net could streamline the experimental approach and may facilitate cardiovascular research.

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“…Cutaneous arteries have a unique property to respond to changes in temperature: Low temperature causes the enhancement of contraction. 1) Although α 2C -adrenoceptors have been proposed to be involved in the enhanced contractile response, [2][3][4] our previous studies showed that α 1A -adrenoceptors also contribute to the enhancement at low temperature in rat tail arteries. 5) In addition, a well correlation between the enhanced contractile response to phenylephrine at low temperature and the expression level of α 1A -adrenoceptors was accompanied with a less contribution of voltage-dependent Ca 2+ channels (VDCC) to the contraction induced by phenylephrine in rat tail arteries.…”

Section: Introductionmentioning

confidence: 90%

Mechanism of Membrane Depolarization Involved in α1A-Adrenoceptor-Mediated Contraction in Rat Tail and Iliac Arteries

Ishida

Dohi

Ishikawa

2019

Biological & Pharmaceutical Bulletin

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Our previous studies have shown that phenylephrine-induced contraction of cutaneous arteries is primarily mediated via α 1A-adrenoceptors, but not α 1D-adrenoceptors that generally mediate vascular contraction, and that the larger part of the contraction is induced in a voltage-dependent Ca 2 channel (VDCC)-independent manner. Here, we investigated the mechanism underlying the smaller part of the α 1Aadrenoceptor-mediated contraction, i.e., VDCC-dependent one, in cutaneous arteries. Isometric contraction was measured with wire myograph in endothelium-denuded tail and iliac arterial rings isolated from male Wistar rats. LOE908 (10 µM), a cation channel blocker, partially inhibited the contraction induced by phenylephrine in tail and iliac arteries. Nifedipine (10 µM) further suppressed the phenylephrine-induced contraction that remained in the presence of LOE908 (10 µM) in iliac arteries but barely in tail arteries, suggesting that phenylephrine-induced depolarization in tail arteries is due to the activation of LOE908-sensitive cation channels. In iliac arteries, the contraction induced by A-61603, a specific α 1A-adrenoceptor agonist, was also partially inhibited by LOE908 (10 µM); however, nifedipine had little effect on the A-61603-induced contraction that remained in the presence of LOE908 (10 µM), suggesting that depolarization mediated via α 1A-adrenoceptors is due to the activation of LOE908-sensitive cation channels even in iliac arteries. These results suggest that membrane depolarization mediated via α 1Α-adrenoceptors is caused by cation influx through LOE908-sensitive cation channels. Less contribution of VDCC to phenylephrine-induced contraction in tail arteries compared to in iliac arteries is likely due to that α 1Α-adrenoceptor-mediated activation of VDCC is caused only by depolarization via cation influx through LOE908-sensitive cation channels.

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α1A-Adrenoceptors, but not α1B- or α1D-adrenoceptors, contribute to enhanced contractile response to phenylephrine in cooling conditions in the rat tail artery

Cited by 6 publications

References 25 publications

Automated Detection and Diameter Estimation for Mouse Mesenteric Artery Using Semantic Segmentation

Automated Detection and Diameter Estimation for Mouse Mesenteric Artery Using Semantic Segmentation

Automated Detection and Diameter Estimation for Mouse Mesenteric Artery using Semantic Segmentation

Mechanism of Membrane Depolarization Involved in α<sub>1A</sub>-Adrenoceptor-Mediated Contraction in Rat Tail and Iliac Arteries

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