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Updated: Aug 19, 2026
Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats
Published on: June 28, 2019
Changes in pH increase perfusion pressure of coronary arteries in the rat
Yasushi Horai1, Ken-Ichi Furukawa, Shingo Iwata
1Department of Pharmaceutical Molecular Biology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai.
Insights
Acidic pH causes rat coronary artery contraction via calcium channels, an effect amplified in hypertension. This finding is crucial for understanding ischemic heart disease and developing targeted treatments.
Area of Science:
- Cardiovascular Physiology
- Vascular Biology
- Renal Physiology
Background:
- Coronary artery stricture is a significant factor in ischemic heart disease.
- Understanding the physiological responses of coronary arteries to pH changes is critical.
Purpose of the Study:
- To investigate the effect of pH variations on rat coronary artery contraction.
- To explore the role of hypertension in modulating these responses.
Main Methods:
- Utilized Langendorff perfused hearts to measure coronary artery contractile state via perfusion pressure.
- Administered various pharmacological agents (verapamil, cromakalim, adenosine) and L-arginine analogue to Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR).
Main Results:
- Alkaline pH caused similar increases in perfusion pressure in both WKY and SHR.
- Acidic pH induced a significantly greater increase in perfusion pressure in SHR compared to WKY.
- Acidic pH-induced contraction was attenuated by verapamil, cromakalim, and adenosine.
- Hypertension induced in WKY by N(G)-nitro-L-arginine enhanced the acidic pH-induced contraction.
Conclusions:
- Acidic pH induces rat coronary artery contraction mediated by calcium (Ca2+) influx through voltage-dependent calcium channels.
- Hypertension exacerbates acidic pH-induced coronary artery contraction, suggesting a link to ischemic heart disease pathophysiology.
Abstract:
Stricture of coronary arteries is closely related to ischemic heart disease. The purpose of this study was to examine whether changes in pH caused contraction of rat coronary arteries, as determined using Langendorff perfused hearts. Changing the pH of the perfusate increased perfusion pressure as an indication of the contractile state of coronary arteries. Alkaline pH-induced increase of perfusion pressure in Wistar Kyoto rats (WKY) was almost identical to that of spontaneously hypertensive rats (SHR), whereas acidic pH-induced increase in SHR was much greater than that in WKY. Acidic pH-induced increase in perfusion pressure was inhibited by verapamil, cromakalim, and adenosine. Feeding WKY with N(G)-nitro-L-arginine resulted in hypertension followed by enhanced acidic pH-induced increase in perfusion pressure. These results suggest that acidic-pH induced contraction of rat coronary arteries is caused by Ca(2+) influx through voltage-dependent Ca(2+) channels and the contraction is enhanced by hypertension.
