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., Brooks, H.L., X, J. and Ganong, W.F. (2019). Ganong’s review of medical physiology. 26th ed. New York: Mcgraw-Hill Education