Increased calcium influx mediates increased cardiac stiffness in hyperthyroid rats
Article
Article Title | Increased calcium influx mediates increased cardiac stiffness in hyperthyroid rats |
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ERA Journal ID | 2172 |
Article Category | Article |
Authors | Levick, Scott (Author), Fenning, Andrew (Author) and Brown, Lindsay (Author) |
Journal Title | Cell Biochemistry and Biophysics |
Journal Citation | 43 (1), pp. 53-60 |
Number of Pages | 8 |
Year | 2005 |
Place of Publication | Totowa, NJ, United States |
ISSN | 1085-9195 |
1559-0283 | |
Abstract | Cardiac remodeling (hypertrophy and fibrosis) and an increased left ventricular diastolic stiffness characterize models of hypertension such as the SHR and DOCA-salt hypertensive rats. By contrast, hyperthyroidism induces hypertrophy and hypertension, yet collagen expression and deposition is unchanged or decreased, whereas diastolic stiffness is increased. We determined the possible role of increased calcium influx in the development of increased diastolic stiffness in hyperthyroidism by administering verapamil (15 mg/[kg x d] orally) to rats given triiodothyronine (T3) (0.5 mg/[kg x d] subcutaneously for 14 d). Administration of T3 significantly increased body temperature (control: 36.7 +/- 0.2 degrees C; T3: 39.6 +/- 0.2 degrees C), left ventricular wet weight (control: 2.09 +/- 0.02 mg/kg; T3 3.07 +/- 0.07 mg/kg), systolic blood pressure (control: 128 +/- 5 mmHg; T3: 156 +/- 4 mmHg), and left ventricular diastolic stiffness (control: 20.6 +/- 2.0; T3: 28.8 +/- 1.4). Collagen content of the left ventricle was unchanged. Contractile response to noradrenaline in thoracic aortic rings was reduced. Relaxation in response to acetylcholine (ACh) was also reduced in T3-treated rats, whereas sodium nitroprusside response was unchanged. Verapamil treatment of hyperthyroid rats completely prevented the increased diastolic stiffness and systolic blood pressure while attenuating the increased body temperature and left ventricular weight; collagen content remained unchanged. ACh response in thoracic aortic rings was restored by verapamil. Thus, in hyperthyroid rats, an increased calcium influx is a potential mediator of the increased diastolic stiffness independent of changes in collagen. |
Keywords | calcium; diastolic stiffness; hyperthyroidism; rat; endothelial dysfunction |
ANZSRC Field of Research 2020 | 319999. Other biological sciences not elsewhere classified |
310999. Zoology not elsewhere classified | |
320101. Cardiology (incl. cardiovascular diseases) | |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | University of Queensland |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q0y9z/increased-calcium-influx-mediates-increased-cardiac-stiffness-in-hyperthyroid-rats
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