Peng Y.-I.KUO-CHU CHANG2020-06-302020-06-3020000008-4212https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034042554&doi=10.1139%2fy00-005&partnerID=40&md5=79c9ff2c187a89b12451af17a2f6fd00https://scholars.lib.ntu.edu.tw/handle/123456789/507183We determined the acute effects of methoxamine, a specific α1- selective adrenoceptor agonist, on the left ventricular-arterial coupling in streptozotocin (STZ)-diabetic rats, using the end-systolic pressure-stroke volume relationships. Rats given STZ 65 mg · kg-1 iv (n = 8) were compared with untreated age-matched controls (n = 8). A high-fidelity pressure sensor and an electromagnetic flow probe measured left ventricular (LV) pressure and ascending aortic flow, respectively. Both LV end-systolic elastance E(LV,ES) and effective arterial elastance E(a) were estimated from the pressure- ejected volume loop. The optimal afterload Q(load) determined by the ratio of E(a) to E(LV,ES) was used to measure the optimality of energy transmission from the left ventricle to the arterial system. In comparison with controls, diabetic rats had decreased LV end-systolic elastance E(LV,ES), at 513 ± 30 vs. 613 ± 29 mmHg · mL-1, decreased effective arterial elastance E(a), at 296 ± 20 vs. 572 ± 48 mmHg · mL-1, and decreased optimal afterload Q(load), at 0.938 ± 0.007 vs. 0.985 ± 0.009. Methoxamine administration to STZ-diabetic rats significantly increased LV end-systolic elastance E(LV,ES), from 513 ± 30 to 602 ± 38 mmHg · mL-1, and effective arterial elastance E(a), from 296 ± 20 to 371 ± 28 mmHg · mL-1, but did not change optimal afterload Q(load). We conclude that diabetes worsens not only the contractile function of the left ventricle, but also the matching condition for the left ventricular-arterial coupling. In STZ-diabetic rats, administration of methoxamine improves the contractile status of the ventricle and arteries, but not the optimality of energy transmission from the left ventricle to the arterial system.Effective arterial elastance; Left ventricular end-systolic elastance; Left ventricular-arterial coupling; Optimal afterload; Streptozotocin-diabetic rats[SDGs]SDG3methoxamine; animal experiment; animal model; animal tissue; aorta flow; artery compliance; article; drug effect; heart afterload; heart left ventricle function; heart left ventricle pressure; male; nonhuman; priority journal; rat; streptozocin diabetesjournal article10.1139/y00-005108414372-s2.0-0034042554