Biomaterial Database

Evidence that glial cells modulate extracellular pH transients induced by neuronal activity in the leech central nervous system. 1994

C R Rose, and J W Deitmer

Abteilung für Allgemeine Zoologie, Universität Kaiserslautern, Germany.

1. The role of the giant neuropile glial cells in the buffering of activity-related extracellular pH changes was studied in segmental ganglia of the leech Hirudo medicinalis L. using pH-sensitive microelectrodes and a slow, two-electrode voltage-clamp system. Neuronal activity was induced by electrical stimulation of a ganglionic side nerve (20 Hz, 1 min). 2. In CO2-HCO3(-)-buffered saline the glial cells were depolarized by 6.5 +/- 2.3 mV and alkalinized by 0.024 +/- 0.006 pH units (mean +/- SD) during the stimulation. The stimulation induced an acidification of 0.032 +/- 0.006 pH units in the extracellular spaces (ECS). 3. Voltage clamping the glial cells suppressed the stimulus-induced glial depolarization and turned the intraglial alkalinization into an acidification of 0.045 +/- 0.021 pH units (n = 6) that closely resembled the acidification observed in the presence of the anion transport blocker DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid, 0.5 mM), and in CO2-HCO(3-)-free saline. 4. Voltage clamping the glial cell resulted in the appearance of a distinct stimulus-induced extracellular alkalinization of 0.024 +/- 0.013 pH units at the onset of the stimulation, as also observed during DIDS application and in the absence of CO2-HCO3-. 5. The results suggest that glial uptake of bicarbonate is mediated by depolarization-induced activation of the electrogenic Na(+)-HCO3- cotransport, which suppresses the profound alkalinization of the ECS during neuronal activity. This is the first direct evidence the glial cells actively modulate extracellular pH changes in a voltage-dependent manner.

UI	MeSH Term	Description	Entries
D007865	Leeches	Annelids of the class Hirudinea. Some species, the bloodsuckers, may become temporarily parasitic upon animals, including man. Medicinal leeches (HIRUDO MEDICINALIS) have been used therapeutically for drawing blood since ancient times.	Hirudinea,Hirudineas,Leeche
D009457	Neuroglia	The non-neuronal cells of the nervous system. They not only provide physical support, but also respond to injury, regulate the ionic and chemical composition of the extracellular milieu, participate in the BLOOD-BRAIN BARRIER and BLOOD-RETINAL BARRIER, form the myelin insulation of nervous pathways, guide neuronal migration during development, and exchange metabolites with neurons. Neuroglia have high-affinity transmitter uptake systems, voltage-dependent and transmitter-gated ion channels, and can release transmitters, but their role in signaling (as in many other functions) is unclear.	Bergmann Glia,Bergmann Glia Cells,Bergmann Glial Cells,Glia,Glia Cells,Satellite Glia,Satellite Glia Cells,Satellite Glial Cells,Glial Cells,Neuroglial Cells,Bergmann Glia Cell,Bergmann Glial Cell,Cell, Bergmann Glia,Cell, Bergmann Glial,Cell, Glia,Cell, Glial,Cell, Neuroglial,Cell, Satellite Glia,Cell, Satellite Glial,Glia Cell,Glia Cell, Bergmann,Glia Cell, Satellite,Glia, Bergmann,Glia, Satellite,Glial Cell,Glial Cell, Bergmann,Glial Cell, Satellite,Glias,Neuroglial Cell,Neuroglias,Satellite Glia Cell,Satellite Glial Cell,Satellite Glias
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D002490	Central Nervous System	The main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.	Cerebrospinal Axis,Axi, Cerebrospinal,Axis, Cerebrospinal,Central Nervous Systems,Cerebrospinal Axi,Nervous System, Central,Nervous Systems, Central,Systems, Central Nervous
D005110	Extracellular Space	Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.	Intercellular Space,Extracellular Spaces,Intercellular Spaces,Space, Extracellular,Space, Intercellular,Spaces, Extracellular,Spaces, Intercellular
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
D001639	Bicarbonates	Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.	Bicarbonate,Bicarbonate Ions,Hydrogen Carbonates,Bicarbonate Ion,Carbonic Acid Ions,Hydrogen Carbonate,Carbonate, Hydrogen,Carbonates, Hydrogen,Ion, Bicarbonate,Ions, Bicarbonate,Ions, Carbonic Acid
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D017878	4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid	An inhibitor of anion conductance including band 3-mediated anion transport.	4,4'-Diisothiocyano-2,2'-Stilbene Disulfonic Acid,DIDS