Tia T. DeFeo

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The bioluminescent calcium indicator aequorin was chemically loaded into isolated strips of ferret portal vein and ferret aorta. Aequorin light emission (a function of [Ca2+]i) was recorded simultaneously with tension. Assuming an [Mg2+]i of 0.5 mM, [Ca2+]i was 1.8 X 10(-7) M in the unstimulated portal vein at 22 degrees C where there was negligible resting(More)
The effects of amrinone and related agents were studied in mammalian cardiac and vascular smooth muscle preparations loaded intracellularly with aequorin, a bioluminescent calcium indicator that emits light when it combines with Ca++. In cat papillary muscles, the effects of amrinone on the amplitude and time course of the aequorin light signal, as they(More)
Enzymatically isolated single cells from ferret portal vein were loaded with the fluorescent dyes fura-2 and chlortetracycline. Ferret portal vein intact strips were loaded with the luminescent indicator aequorin. At short loading times, fura-2 loading resulted in relatively homogeneous images of labeled cells. At longer loading times, extremely(More)
The bioluminescent calcium indicator aequorin was successfully loaded into mammalian working myocardium of ferrets by a chemical procedure which makes the cells reversibly hyperpermeable through exposure to Ethylenebis-(oxyethylenenitrilo) tetraacetic acid (EGTA). After undergoing the loading procedure, developed tension at Lmax was 103±26% of the control,(More)
A modified method for enzymatically isolating mammalian vascular smooth muscle cells has been developed and tested for ferret portal vein smooth muscle. This method produces a high proportion of fully relaxed cells and these cells appear to have normal pharmacological responsiveness. The ED50 values for both alpha stimulation and potassium depolarization(More)
A comparison between the fluorescent indicator quin 2 and the bioluminescent indicator aequorin was performed in the same smooth muscle cell type. Aequorin was loaded into intact strips and quin was loaded into enzymatically isolated single cells from ferret portal vein. Both indicators gave qualitatively the same calcium profiles when the tissue was(More)
We studied stimulus-specific alterations of the excitation-contraction coupling pathway in freshly isolated contractile and subcultured non-contractile vascular smooth muscle cells. Using the calcium indicator aequorin, we detected physiological increases in cytoplasmic free calcium ([Ca2+]i) in subcultured smooth muscle cells subjected to angiotensin or 33(More)
1. The effects of three vasodilators, nifedipine, hydralazine and forskolin, were determined on isometric force and intracellular ionized calcium concentration ([Ca2+]i) as indicated by aequorin in ferret aorta. Three types of contraction were studied: the intrinsic tone induced by warming from 22 to 37 degrees C; the contraction to the phorbol ester(More)
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