Cellular Homeostasis -APS Refresher Course 2004 “In the beginning … there was the cell” Michael F. Romero, PhD Depts. Physiology & Biophysics and Pharmacology Case Western Reserve University, Cleveland, OH http://RomeroSnap1.phol.cwru.edu/index.htm APS Professional Education  http://www.the-aps.org/education/edu_grad.html APS Refresher Courses  http://www.the-aps.org/education/edu_misc/refresh.htm

glutamate dehydrogenase System/Organ Physiology Levels of Homeostasis nHCO3- NBC1 Na+ H+ ATPase 3Na+ 2K+ Blood CO2 H2O NHE3 gln Glut CA-2 Gln Glu- α-KG glutaminase glutamate dehydrogenase 2 NH3 2 NH4+ System/Organ Physiology I Organism Physiology Cell & Molecular Physiology

Genetic Control -nucleus Cellular Structure Genetic Control -nucleus Question: How does the Cell “know” to organize & control cell functions? Energy Control -mitochondria Answer = Cellular Homeostasis © Boron & Boulpaep (2003), Medical Physiology, Saunders

Agenda – Cellular Homeostasis post Genome(s) 8:00 – 8:10 In the beginning… there was the cell. M.F. Romero, Case Western Res. Univ. 8:10 – 9:00 Generation of membrane potential. S. Wright, Univ. of Arizona Col. of Med. 9:00 – 9:50 Cellular ionic homeostasis / channel-transporter physiology. G.R. Dubyak, Case Western Res. Univ. 9:50 – 10:00 Break / Coffee/ Tea 10:00 – 10:50 Cellular volume homeostasis. K. Strange, Vanderbilt Univ. 10:50 – 11:40 Cellular pH homeostasis. W.F. Boron, Yale Univ. 11:40 – 12:00 Final Discussion - All participants

Nernst Equation at Equilibrium: 8:10 Generation of membrane potential. Steve Wright, Univ. of Arizona Col. of Med. at Equilibrium: Electrical Force = Chemical Force (electrical ‘voltage’ = chemical ‘gradient’) VKzKF = -RT ln [K+]in [K+]out Maybe lightning bolt for “electrical force” Bubbling beaker/flask for “chemical force” VK = ln [K+]in [K+]out -RT zKF Nernst Equation

25 Na+ 90 K+ 1e-4 Ca2+ 0.8 Mg2+ 35 Cl- 12 HCO3– 0.7 PO43- 0.7 SO42- Mammalian Cell Gradients Extracellular 25 Na+ 90 K+ 1e-4 Ca2+ 0.8 Mg2+ 35 Cl- 12 HCO3– 0.7 PO43- 0.7 SO42- Intracellular Interstitial space 145 Na+ 5 K+ 1 Ca2+ 0.8 Mg2+ 104 Cl- 25 HCO3– 1 PO43- 1 SO42- Vm ~ -60mV Background: RGB = 255, 215, 175 Interstitial Fluid: RGB = 178, 220, 255 Cell interior: RGB = 169, 207, 161 Cell membrane: from left -> 5 down. Cell membrane fill: 5 less than WHITE. CA II fill: 3 less than WHITE. Other Transporter fill: from right -> 2 up, 3 over CO2 Icon fill: RGB = 203, 125, 164

Mammalian Cell Gradients 145 Na+ 5 K+ 104 Cl- Extracellular Interstitial space Vm ~ -60mV 25 Na+ 90 K+ 35 Cl- Intracellular Na+ K+ Background: RGB = 255, 215, 175 Interstitial Fluid: RGB = 178, 220, 255 Cell interior: RGB = 169, 207, 161 Cell membrane: from left -> 5 down. Cell membrane fill: 5 less than WHITE. CA II fill: 3 less than WHITE. Other Transporter fill: from right -> 2 up, 3 over CO2 Icon fill: RGB = 203, 125, 164 Cl-

9:00 Cellular ionic homeostasis/channel-transporter physiology 9:00 Cellular ionic homeostasis/channel-transporter physiology. George R. Dubyak, Case Western Res. Univ. Lodish et al. (2000) Molecular Cell Biology 4th Edition [W.H. Freeman & Co.]

10:00 Cellular volume homeostasis. Kevin Strange, Vanderbilt Univ. Cell volume is regulated by the gain and loss of osmotically active solutes normal volume Regulatory Volume Increase (RVI) Decrease (RVD) solute gain solute loss

10:50 Cellular pH homeostasis. Walter F. Boron, Yale Univ. Systemic pH regulation

10:50 Cellular pH homeostasis. Walter F. Boron, Yale Univ. Regulation: Acid extruders & loaders H+ OH– Na+ Cl– HCO3 – 2 V-type H+ pump Na-H Exchanger Na-Driven Cl-HCO3 Exchanger Na/HCO3 Cotransporter (1:2 stoichiometry) 3 (1:3 stoichiometry) Cl-HCO3 Exchanger Acid Extruders Acid Loaders pHi Metabolism Cellular pH regulation

Agenda – Cellular Homeostasis 8:00 – 8:10 In the beginning… there was the cell. M.F. Romero, Case Western Res. Univ. 8:10 – 9:00 Generation of membrane potential. S. Wright, Univ. of Arizona Col. of Med. 9:00 – 9:50 Cellular ionic homeostasis / channel-transporter physiology. G.R. Dubyak, Case Western Res. Univ. 9:50 – 10:00 Break / Coffee/ Tea 10:00 – 10:50 Cellular volume homeostasis. K. Strange, Vanderbilt Univ. 10:50 – 11:40 Cellular pH homeostasis. W.F. Boron, Yale Univ. 11:40 – 12:00 Final Discussion - All participants