Acid-base regulation during hypothermia. a brief review

Area of Science:

• Physiology
• Biochemistry

Background:

• Acid-base physiology traditionally focuses on extracellular pH, particularly arterial blood.
• Normal arterial blood pH in mammals is maintained around 7.39-7.42 through buffering, ventilation, and kidney function.

Purpose of the Study:

• To investigate intracellular pH and its physiological significance.
• To understand the transmembrane hydrogen ion gradient in relation to cellular metabolism.

Main Methods:

• Measurement of intracellular pH.
• Analysis of ionization constants of water-soluble biosynthetic intermediates.

Main Results:

• Intracellular fluid pH is found to be close to neutrality, around 6.8.
• A significant transmembrane hydrogen ion gradient exists, with intracellular [H+] (160 nmol/L) higher than extracellular [H+] (40 nmol/L).

Conclusions:

• Intracellular pH near neutrality (6.8) optimizes the ionization and retention of intracellular metabolites.
• Maintaining a substantial transmembrane hydrogen ion gradient is crucial for cellular acid-base balance and metabolite management.