ELECTROENDOSMOSIS THROUGH MAMMALIAN SEROUS MEMBRANES : II. COMPARISON OF HYDROGEN ION REVERSAL POINTS WITH ACETATE...

Area of Science:

• Physiological chemistry
• Membrane biophysics

Background:

• Serous membranes exhibit unique hydrogen ion reversal points.
• Previous estimations used citrate-phosphate buffers.

Purpose of the Study:

• To determine and compare hydrogen ion reversal points of human, dog, and cat serous membranes.
• To evaluate the accuracy of acetate buffer mixtures versus citrate-phosphate mixtures.

Main Methods:

• Determining hydrogen ion reversal points using acetic acid-sodium acetate buffer mixtures.
• Comparing these values with those obtained using citrate-phosphate buffer mixtures.
• Assessing reversal points across different species (human, dog, cat) and membrane types (fat, lean).

Main Results:

• Acetate buffer mixtures yielded higher (more alkaline) reversal points compared to citrate-phosphate mixtures.
• Values were approximately 0.25 pH units higher for fat membranes and 0.5 pH units higher for lean membranes.
• Reversal points were characteristic for each membrane and species, with no postmortem shift observed.

Conclusions:

• Acetic acid-sodium acetate buffers provide a more accurate determination of true hydrogen ion reversal points for serous membranes.
• Serous membrane charge is readily and repeatedly reversible, even in living animals.
• Established reversal points are species- and membrane-specific.