Biomaterial Database

Effects of relative hypoxia and hypercapnia on intracellular pH and membrane potential of cultured carotid body glomus cells. 1991

S F He, and J Y Wei, and C Eyzaguirre

Department of Physiology, University of Utah School of Medicine, Salt Lake City 84108.

Clusters of glomus cells, isolated from rat carotid bodies, were cultured for up to 2 weeks. Afterwards, we simultaneously measured the intracellular pH (pHi) and membrane potentials (Em) of single cells with pH-sensitive and KCl-filled microelectrodes. In 89 control cells (bathed in saline equilibrated with 50% O2 in N2) pHi was 6.87 +/- 0.014 (SE) and Em -36.3 +/- 0.45 mV. In 42 cells, switching to air (about 20% O2) lowered pHi in 60% of them by as much as 0.14 unit (mean decrease, 0.05). In the remaining cells, pHi increased by as much as 0.18 unit (mean increase, 0.06). Application of 2.5% CO2 in 50% O2 (balance N2) reduced the pHi in 90% of 47 cells by as much as 0.44 unit (mean decrease, 0.14). pHi increased to a maximum of 0.05 unit (mean increase, 0.04) in the others. Either stimulus depolarized or hyperpolarized glomus cells (-5 to 8 mV) in approximately equal proportions. There was a significant and positive correlation between delta Em and delta pHi. This observation confirms the idea that the Em of glomus cell is H(+)-dependent. Results do not agree with the acidic hypothesis for chemoreception.

UI	MeSH Term	Description	Entries
D007425	Intracellular Membranes	Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Membranes, Intracellular,Intracellular Membrane,Membrane, Intracellular
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D002344	Carotid Body	A small cluster of chemoreceptive and supporting cells located near the bifurcation of the internal carotid artery. The carotid body, which is richly supplied with fenestrated capillaries, senses the pH, carbon dioxide, and oxygen concentrations in the blood and plays a crucial role in their homeostatic control.	Glomus Caroticum,Bodies, Carotid,Body, Carotid,Caroticum, Glomus,Carotid Bodies
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia