[The sarcoplasmic reticulum Ca2+ handling protein and left ventricular hypertrophy in SHR].
OBJECTIVE
To elucidate the role of myocardial angiotensin II and sarcoplasmic reticulum (SR) Ca2+ handling protein (ryanodine receptor and Ca2+ ATPase) in the process of left ventricular hypertrophy.


METHODS
The myocardial angiotensin II level, Bmax and Kd value of ryanodine receptor and calcium ATPase activity in SR were determined among 3 groups: spontaneously hypertensive rats (SHR), SHR treated with perindopril and WKY.


RESULTS
The blood pressure (BP) of the SHR group, the ratio of left ventricular weight to body weight (LVW/BW) and the myocardial angiotensin II level were higher than those of the WKY group (P < 0.01), Perindopril decreased the BP(P < 0.01) and the myocardial angiotensin II level, and reversed the LVW/BW of the SHR group (P < 0.05). Compared to the WKY group, the Bmax value of cardiac ryanodine receptor in the SHR group was increased (232 +/- 27) fmol.mg-1 vs (173 +/- 18) fmol.mg-1, (P < 0.01), but there was no difference in Kd value (P > 0.05). The SR calcium ATPase activity was also decreased in the SHR group [(0.52 +/- 0.11) mumol.g-1.min-1 vs (1.03 +/- 0.22) mumol.g-1.min-1, P < 0.01]. In the SHR perindopril treatment group, the Bmax of ryanodine receptor was decreased [(191 +/- 23) fmol.mg-1, P < 0.05]. There was no difference in Kd value. The calcium ATPase activity was increased [(0.82 +/- 0.28) mumol.g-1.min-1, P < 0.05)].


CONCLUSIONS
The left ventricular hypertrophy is closely related to the myocardial angiotensin II and the SR calcium handling protein.
Zhu
B
B
Department of Cardiology, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029.
Zhang
J
J
Liu
N
N
D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D006973:Hypertension / Q000150:complications / Q000378:metabolism*; D017379:Hypertrophy, Left Ventricular / Q000209:etiology / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D019837:Ryanodine Receptor Calcium Release Channel; D000804:Angiotensin II; D000252:Calcium-Transporting ATPases