https://scholars.lib.ntu.edu.tw/handle/123456789/507178
Title: | Systolic elastance and resistance in the regulation of cardiac pumping function in early streptozotocin-diabetic rats | Authors: | KUO-CHU CHANG Lo H.-M. Tseng Y.-Z. |
Keywords: | Cardiac systolic mechanics; Effective arterial volume elastance; Maximal systolic elastance; Streptozotocin-diabetic rats; Theoretical maximum flow | Issue Date: | 2002 | Journal Volume: | 227 | Journal Issue: | 4 | Start page/Pages: | 251-259 | Source: | Experimental Biology and Medicine | Abstract: | We determined the roles of maximal systolic elastance (Emax) and theoretical maximum flow (Q?max) in the regulation of cardiac pumping function in early streptozotocin (STZ)-diabetic rats. Physically, Emax can reflect the intrinsic contractility of the myocardium as an intact heart, and Q?max has an inverse relation to the systolic resistance of the left ventricle. Rats given STZ 65 mg/kg i.v. (n = 17) were divided into two groups, 1 week and 4 weeks after induction of diabetes, and compared with untreated age-matched controls (n = 15). Left ventricular (LV) pressure and ascending aortic flow signals were recorded to calculate Emax and Q?max, using the elastance-resistance model. After 1 or 4 weeks, STZ-diabetic animals show an increase in effective LV end-diastolic volume (Veed), no significant change in peak isovolumic pressure (Pisomax), and a decline in effective arterial volume elastance (Ea). The maximal systolic elastance Emax is reduced from 751.5 ± 23.1 mmHg/ml in controls to 514.1 ± 22.4 mmHg/ml in 1- and 538.4 ± 33.8 mmHg/ml in 4-week diabetic rats. Since Emax equals Pisomax/Veed an increase in Veed with unaltered Pisomax may primarily act to diminish Emax so that the intrinsic contractility of the diabetic heart is impaired. By contrast, STZ-diabetic rats have higher theoretical maximum flow Q?max (40.9 ± 2.8 ml/s in 1- and 44.5 ± 3.8 ml/s in 4-week diabetic rats) than do controls (30.7 ± 1.7 ml/s). There exists an inverse relation between Q?max and Ea when a linear regression of Q?max on Ea is performed over all animals studied (r = 0.65, p < 0.01). The enhanced Q?max is indicative of the decline in systolic resistance of the diabetic rat heart. The opposing effects of enhanced Q?max and reduced Emax may negate each other, and then the cardiac pumping function of the early STZ-diabetic rat heart could be preserved before cardiac failure occurs. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036554099&partnerID=40&md5=3fc5f04bb6402651289681667e9a94ec https://scholars.lib.ntu.edu.tw/handle/123456789/507178 |
ISSN: | 0037-9727 | SDG/Keyword: | insulin; streptozocin; animal experiment; animal model; aorta flow; artery compliance; article; compliance (physical); controlled study; heart function; heart muscle contractility; hemodynamics; insulin treatment; male; nonhuman; rat; regulatory mechanism; streptozocin diabetes; systole; Animalia |
Appears in Collections: | 生理學科所 |
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