M. Pilar Ramírez-Ponce

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Macroscopic membrane currents of white adipocytes were studied using the whole-cell variant of the patch-clamp technique. These cells were obtained by differentiating preadipocytes fro rat epididymal tissue. In all differentiated cells outward currents exhibiting sigmoidal activation kinetics were observed with amplitudes ranging from 0.5 to 6 nA. The(More)
We studied the potassium currents in white adipocytes obtained by culturing preadipocytes from rat epididymal tissue, both with insulin (WA(i)) and without insulin (WA(o)), in order to test the role of insulin in the development of voltage-gated potassium channels (K(v)) during adipogenesis. Occasionally, very small potassium currents (I(K,V)) were present(More)
An active change in membrane voltage responses to hyperpolarizing pulses has been identified by intracellular recording on an in vitro preparation of white adipose tissue. This change was characterized by a slow return to baseline at the offset of the pulses. Amplitude and duration of the slow return to baseline were dependent on extracellular K+(More)
The role of rhodoquinone and ubiquinone in the oxygen photoreducing (photooxidase) activity of Rhodospirillum rubrum was investigated. The sole addition of purified rhodoquinone restored photooxidase activity in isolated chromatophores which had been extracted with organic solvents and which were apparently free of secondary acceptor ubiquinone.(More)
Intracellular recording of white adipocytes was performed in an in vitro preparation. Resting potential, input resistance and membrane time constant averaged: -34 +/- 9 mV, 295 +/- 161 M omega, and 58 +/- 19 ms respectively (mean +/- SD, n = 32). Intracellular injection of positive and negative square current pulses elicited membrane voltage responses,(More)
We studied the effect of the external addition of noradrenaline (NA) on the electrical activity of white adipocytes from rat epididymal tissue. NA modified the active voltage response recorded by the current clamp technique, and decreased the macroscopic membrane potassium currents measured by a whole-cell configuration patch-clamp technique in cells(More)
The whole-cell patch-clamp method was used to study the membrane electrical properties of human adipocyte cells obtained by differentiating from precursors of human abdominal and mammary tissues. All differentiated cells exhibited outward currents with sigmoidal activation kinetics. The outward currents showed activation thresholds between −20 to −30 mV and(More)
We have investigated the effect of the redox state of added NAD on the rates of anaerobic cyclic photophosphorylation which are supported by membrane vesicles isolated from Rhodospirillum rubrum. As the redox potential of NAD was lowered, the activity decreased according to a typical potentiometric titration. The Nernst plot showed an apparent midpoint(More)
5-hydroxytriptamine (5-HT, serotonin) storage and release in mast cell (MC) secretory granules (SG) are dependent on serglycin proteoglycans (PG). This notion is based on the studies of MC of the connective tissue subtype that predominantly contain PG of the heparin type, whereas intestinal mucosal MC, which contain predominantly chondroitin sulfate, have(More)