Aiello E A, Grassi de Gende A O
Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Argentina.
Jpn Heart J. 1995 Mar;36(2):247-57. doi: 10.1536/ihj.36.247.
The release of 45Ca induced by Ca2+ was studied in genetically hypertensive (SHR) and normotensive (WKY) rats using EGTA-skinned aortic strips. Strips preloaded with 45Ca (pCa 6.6) were desaturated at 5 mM of EGTA. A slow component of the washout in aorta from SHRs exhibited higher Ca content and a lower rate of Ca leak than that in aorta from WKY rats. This slow component was stimulated during washing with 0.03, 0.3, 1 or 10 microM free Ca2+. The release of 45Ca induced by Ca2+ proceeded at similar rates in preparations of the two strains. Compared to WKY aortic strips the stimulated efflux of 45Ca was greater in SHR aortic strips due to the higher Ca content. About half of the release of 45Ca induced by 1 microM free Ca2+ during the first 6 minutes of stimulation was blocked by 0.6 mM of ryanodine or 50 microM of ruthenium red, thus identifying the sarcoplasmic reticulum as a source of Ca release. The results suggest that this intracellular storage of Ca in aorta from genetically hypertensive rats is relevant for the generation of high levels of cytosolic Ca2+.
使用EGTA透皮主动脉条研究了遗传性高血压大鼠（SHR）和正常血压大鼠（WKY）中Ca2+诱导的45Ca释放。预加载45Ca（pCa 6.6）的条带在5 mM EGTA中去饱和。SHR主动脉条洗脱的慢成分显示出比WKY大鼠主动脉条更高的钙含量和更低的钙泄漏率。在用0.03、0.3、1或10 microM游离Ca2+冲洗期间，该慢成分受到刺激。Ca2+诱导的45Ca释放在两种品系的制剂中以相似的速率进行。与WKY主动脉条相比，由于Ca含量较高，SHR主动脉条中刺激的45Ca流出量更大。在刺激的前6分钟内，1 microM游离Ca2+诱导的45Ca释放约一半被0.6 mM的ryanodine或50 microM的钌红阻断，从而确定肌浆网是Ca释放的来源。结果表明，遗传性高血压大鼠主动脉中这种细胞内钙储存与高水平胞质Ca2+的产生有关。
