The Unique Renal Myogenic Response:A Mechanism Protecting Against Hypertensive Injury
作者单位：Smooth Muscle Research Group University of Calgary Faculty of Medicine Calgary Alberta Canada
会议名称：《第十五届国际药理学大会》
会议日期：2006年
学科分类：1002[医学-临床医学] 100201[医学-内科学(含：心血管病、血液病、呼吸系病、消化系病、内分泌与代谢病、肾病、风湿病、传染病)] 10[医学]
摘 要：正 Hypertension is a leading factor in the onset and progression of chronic kidney disease （CKD）. Elevations in systolic blood pressure （SBP） are most closely linked to CKD as is impaired renal autoregulation. Indeed, animal studies show an invariant relationship between impaired autoregulation and hypertensive glomerular injury. The myogenic response of the afferent arteriole （AA） contributes to autoregulation and is uniquely suited to a role in renal protection. We have found that, in the rat. pressure increases initiate a rapid AA vasoconstriction within 200-300 ms. When pressure is reduced, vasodilation is intitiated after a much longer delay （-1s） and high-speed video studies show that vasoconstrictor responses initiated by short pressure pulses （ 300 ms） continue during this delay . Experimental and modeling approaches demonstrate that these features allow the AA to sense and adjust steady-state myogenic tone in response to the rapidly oscillating SBP signal, thereby attenuating the transmission of pressure transients to the glomerulus. Studies of the mechanisms underlying the unusual kinetics implicate intracellular Ca release and the AA expression of the cardiac ryanodine receptor isoform （RyR2）.