INTRACELLULAR CALCIUM

SUMMARY

1. Ca regulates many physiologic processes: proliferation, neural signaling, learning, contraction, secretion, fertilization.

2. Intracytoplasmic Ca concentration: 100nmol/l; stored in ER and other organelles.

3. Interstitial Ca concentration 12,000x greater, hence Ca has an inward electrochemical gradient.

4. Ca enters cells via ligand-gated, voltage-gated (transient vs. long-standing), stretch-activated channels.

5. Ca removal from cell by: Ca-ATPase, Ca-Na antiport.

6. Ca movement into internal stores via sarcoplasmic or endoplasmic reticulum Ca-ATPase (SERCA) pump.

7. Store-operated Ca channels allow intracellular Ca stores to be replenished.

Reference(s)

Barrett, K.E., Barman, S.M., Boitano, S., Brooks, H.L., Weitz, M., Brian Patrick Kearns, Ganong, W.F. and Mcgraw-Hill Education (Firm (2016). Ganong’s review of medical physiology. 25th ed. New York: Mcgraw Hill Education.
Hall, J.E. and Hall, M.E. (2020). Guyton And Hall Textbook Of Medical Physiology. 14th ed. S.L.: Elsevier - Health Science.
West, J.B. and Luks, A.M. (2021). West’s Pulmonary Pathophysiology. Lippincott Williams & Wilkins.