PT  - JOURNAL ARTICLE
AU  - Brent J. F. Hill
AU  - Laxmansa C. Katwa
AU  - Brian R. Wamhoff
AU  - Michael Sturek
TI  - Enhanced Endothelin<sub>A</sub> Receptor-Mediated Calcium Mobilization and Contraction in Organ Cultured Porcine Coronary Arteries
DP  - 2000 Nov 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 484--491
VI  - 295
IP  - 2
4099  - http://jpet.aspetjournals.org/content/295/2/484.short
4100  - http://jpet.aspetjournals.org/content/295/2/484.full
SO  - J Pharmacol Exp Ther2000 Nov 01; 295
AB  - Arterial injury models for coronary artery disease have demonstrated an enhanced expression and function of either the endothelinAor endothelinB (ETA or ETB) receptor subtype. We hypothesized that organ culture would enhance the physiological function of ET receptors in the porcine right coronary artery. Arteries were either cold stored (4°C) or organ cultured (37°C) for 4 days. After 4 days, the artery was either 1) sectioned into rings to measure the ET-1-induced isometric tension response (3 × 10−10–3 × 10−7 M), or 2) enzymatically dispersed and the isolated smooth muscle cells imaged using fura-2 to measure the myoplasmic calcium (Cam) response to 3 × 10−8 M ET-1 (∼EC50). Isometric tension and Cam to ET-1 were measured in the absence and presence of bosentan (nonselective ETA or ETB receptor antagonist), BQ788 (ETB-selective antagonist), and BQ123 (ETA-selective antagonist). Compared with cold storage, organ culture induced a 2-fold increase in tension development (3 × 10−7 M ET-1) and Cam(3 × 10−8 M ET-1), which was inhibited with bosentan, thus confirming the enhanced responses to ET-1 were due to ET receptor activation. BQ123 also inhibited the enhanced contraction and Cam responses to ET-1. In contrast, BQ788 failed to inhibit tension development and Cam responses to ET-1 in organ culture and cold storage. Sarafotoxin 6C (ETB agonist) failed to elicit an increased Cam response in organ culture compared with cold storage. Our results indicate the increased tension development and Cam responses to ET-1 in organ culture are attributable to ETA receptors, and not ETBreceptors. The American Society for Pharmacology and Experimental Therapeutics