Virginia A. Posey

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The effects of monovalent cations on the active calcium-accumulating ability of cardiac sarcoplasmic reticulum were assessed. Grana prepared in an ion-free system accumulated calcium when ATP and Mg(++) were present. Sodium ion and to a lesser extent lithium but not K(+) reduced the amount of calcium taken up. The reduction of calcium binding by Na(+) is(More)
Electrical and mechanical activity of segments of isolated human Fallopian tubes was recorded with the use of extracellular pore electrodes and a transducer recording tension in the longitudinal axis. Electrical activity was regularly recorded in ampullar segments of tubes from premenopausal women and consisted usually of one spike apparently preceded by(More)
The structural basis for myogenic and neurogenic control of motility of human Fallopian tubes was studied. In the ampulla distinct muscle layers were absent, and bundles of cells oriented in different axes were in contact with one another by means of randomly located simple apposition contacts; no nexuses were present. The organization was consistent with a(More)
Calcium binds to membranous structures isolated from rabbit kidney cortex homogenates. The binding is enhanced by ATP and Mg(++) in combination. Other nucleotides, ITP and GTP, do not have this property. In contrast to similar preparations of nerve and muscle, the binding is not augmented by oxalate (3-100 mM). Also, binding of calcium cannot be correlated(More)
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