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Role of AT2 receptor in the cardioprotective response induced by thyroid hormone
Author(s) -
Barreto-Chaves Maria Luiza Morais,
Gomes Dayane Aparecida,
Tavares Felix Meira
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1139.8
Subject(s) - ventricle , medicine , cardiac function curve , endocrinology , blockade , ischemia , muscle hypertrophy , heart rate , cardiology , heart failure , receptor , blood pressure
We have shown an upregulation of AT2R in heart from hyperthyroid rats. AT2R has been associated to protection heart function from ischemic injury. This study aims to the role of AT2R in the recovery after Ischemia‐Reperfusion (I‐R) with or without AT2R blockade in isolated heart from hyperthyroid rats. T3 (0.7 μg/Kg BW/day, i.p.) was injected to rats in the presence or absence of AT2R blocker (PD) (10 mg/Kg) for 14 days. Rats were divided in groups: control (C); PD; T3 and PD+T3. Hearts were excised and submitted to I‐R protocol in a Langendorff apparatus. A balloon was inserted in the left ventricle to assess Left Ventricular Developed Pressure (LVDP), +dP/dt and ‐dP/dt. After 30 min of stabilization (S), hearts were subjected to 20 min of I and 45 min of R. Cardiac hypertrophy was assessed by heart weight/tibia length ratio. Data (mean±SD) were analyzed by One‐way ANOVA, considering P<0.05. T3 induced cardiac hypertrophy, which was not changed by PD. Cardiac function after I‐R was analyzed as % of change in the end of R compared to the S period. Data were compared to C group. LVDP increased 35% and +dP/dt 23% in T3 and PD groups; ‐dP/dt increased in T3 (27%) and PD (47%) groups. The combination of treatments (PD+T3) was able to return the heart performance in all parameters to the control situation. In conclusion AT2R plays a significant role in I‐R and it is involved to the cardioprotection induced by T3.