- 作者: Jun Ren; Mary F. Walsh; LeQuishia Jefferson; Melissa Natavio; Karl J. Ilg; James R. Sowers; Ricardo A. Brown
- 作者服務機構: Department of Physiology, Wayne State University School of Medicine Detroit, Mich., Department of Pharmacology, Physiology, and Terapeutice, University of North Dakota School of Medicine, Grand Forks, N. Dak., and Department of Interal Medicine, Wayne State University School of Medicine, Detroit, Mich., USA
- 中文摘要: --
- 英文摘要: Obesity plays a pivotal role in metabolic and cardiovas-cular diseases. Certain types of obesity may be related toalcohol ingestion, which itself leads to impaired cardiacfunction. This study analyzed basal and ethanol-inducedcardiac contractile response using left-ventricular papil-lary muscles and myocytes from lean and obese Zuckerrats. Contractile properties analyzed include: peak ten-sion development (PTD), peak shortening amplitude(PS), time to PTD/PS (TPT/TPS), time to 90% relaxation/relengthening (RT90/TR90) and maximal velocities of con-traction/shortening and relaxation/relengthening (士VTand士dL/dt). Intracellular Ca2+transients were measuredas fura-2 fluorescence intensity (AFFI) changes and fluo-rescence decay time (FDT). In papillary muscles fromobese rats, the baseline TPT and RT90 were significantlyprolonged accompanied with low to normal PTD and士VT compared to those in lean rats. Muscles from obesehearts also exhibited reduced responsiveness to postrestpotentiation, increase in extracellular Ca2+ concentration,and norepinephrine. By contrast, in isolated myocytes,obesity reduced PS associated with a significant pro-longed TR90, normal TPS and 士dL/dt. Intracellular Ca2+recording revealed decreased resting Ca2+ levels andprolonged FDT. Acute ethanol exposure (80-640 mg/dl)caused comparable concentration-dependent inhibitionsof PTD/PS and AFFI, associated with reduced 士VT inboth groups. Collectively, these results suggest alteredcardiac contractile function and unchanged ethanol-induced depression in obesity.
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