Physiology Commons^™

Effect Of Muscle Length On Cross-Bridge Kinetics In Intact Cardiac Trabeculae At Body Temperature, Nima Milani-Nejad, Ying Xu, Jonathan P. Davis, Kenneth S. Campbell, Paul M. L. Janssen

Physiology Faculty Publications

Dynamic force generation in cardiac muscle, which determines cardiac pumping activity, depends on both the number of sarcomeric cross-bridges and on their cycling kinetics. The Frank–Starling mechanism dictates that cardiac force development increases with increasing cardiac muscle length (corresponding to increased ventricular volume). It is, however, unclear to what extent this increase in cardiac muscle length affects the rate of cross-bridge cycling. Previous studies using permeabilized cardiac preparations, sub-physiological temperatures, or both have obtained conflicting results. Here, we developed a protocol that allowed us to reliably and reproducibly measure the rate of tension redevelopment (k_tr; which depends …

Ipla2Β Overexpression In Smooth Muscle Exacerbates Angiotensin Ii-Induced Hypertension And Vascular Remodeling, Lindsay E Calderon, Shu Liu, Wen Su, Zhongwen Xie, Zhenheng Guo, Wanda Eberhard, Ming C. Gong

Physiology Faculty Publications

OBJECTIVES: Calcium independent group VIA phospholipase A₂ (iPLA₂β) is up-regulated in vascular smooth muscle cells in some diseases, but whether the up-regulated iPLA₂β affects vascular morphology and blood pressure is unknown. The current study addresses this question by evaluating the basal- and angiotensin II infusion-induced vascular remodeling and hypertension in smooth muscle specific iPLA₂β transgenic (iPLA₂β-Tg) mice.

METHOD AND RESULTS: Blood pressure was monitored by radiotelemetry and vascular remodeling was assessed by morphologic analysis. We found that the angiotensin II-induced increase in diastolic pressure was significantly higher in iPLA₂β-Tg …