PMID- 2358863
OWN - NLM
STAT- MEDLINE
DCOM- 19900731
LR  - 20171213
IS  - 0022-3077 (Print)
IS  - 0022-3077 (Linking)
VI  - 63
IP  - 5
DP  - 1990 May
TI  - Mechanism of potassium uptake in neuropile glial cells in the central nervous 
      system of the leech.
PG  - 1089-97
AB  - 1. Ion-selective double-barreled microelectrodes (ISME) were used to measure 
      intracellular K+ (aKi), Na+ (aNai), and Cl- (aCli) activities of neuropile glial 
      (NG) cells in the central nervous system of the medicinal leech Hirudo 
      medicinalis. Ion fluxes were induced by an increase in extracellular K+ 
      concentration [( K+]o) and analyzed to elucidate the ionic mechanism of the K+ 
      uptake occurring under such conditions. 2. In addition, the K+ concentration of 
      the extracellular space of the nerve cell body region (NCBR) and the neuropile 
      (N) was measured with neutral carrier K(+)-ISME. In normal saline (4 mM K+), a 
      concentration of 4.2 mM was measured in both extracellular spaces. No differences 
      between the K+ concentration of the bathing fluid and the extracellular spaces 
      were found at higher (i.e., 10 and 40 mM) K+ concentrations. 3. In normal saline, 
      the mean membrane potential (Em) was -68 mV, and the mean aKi, aNai, and aCli 
      were found to be 77, 10, and 7 mM, respectively. The corresponding equilibrium 
      potentials were -81, 56, and -66 mV. The chloride equilibrium potential (ECl) was 
      similar to Em, and it is concluded that chloride is passively distributed across 
      the NG cell membrane. 4. When [K+]o was transiently increased 10-fold (i.e., to 
      40 mM), aKi and a Cli increased transiently by 22 and 25 mM, respectively, and 
      the membrane depolarized to -28 mV, which was similar to both K+ equilibrium 
      potential (EK) and ECl. The KCl uptake was accompanied by a transient decrease in 
      aNai to 5 mM. 5. After incubation for at least 1 h in Na(+)-free saline, NG cells 
      accumulated K+ in the absence of extracellular Na+ to levels similar to those 
      observed in the presence of Na+. Therefore the uptake of K+ was not dependent on 
      external--and probably also internal--Na+. 6. Changes in cell volume induced by 
      the increase in [K+]o were estimated by loading NG cells with choline and 
      monitoring its intracellular concentration with Corning-K(+)-ISME. In saline 
      containing 40 mM K+, NG cell volume increased to approximately 150% of its volume 
      in normal saline. 7. It is concluded that the mechanism of K+ uptake in NG cells 
      is by passive KCl and water influx, which causes cell swelling.
FAU - Wuttke, W A
AU  - Wuttke WA
AD  - School of Biological Sciences, University College of Swansea, United Kingdom.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Neurophysiol
JT  - Journal of neurophysiology
JID - 0375404
RN  - 0 (Chlorides)
RN  - 9NEZ333N27 (Sodium)
RN  - RWP5GA015D (Potassium)
SB  - IM
MH  - Animals
MH  - Central Nervous System/metabolism/*physiology
MH  - Chlorides/physiology
MH  - Extracellular Space/metabolism
MH  - Leeches/metabolism/*physiology
MH  - Neuroglia/metabolism/*physiology
MH  - Potassium/*pharmacokinetics/physiology
MH  - Sodium/physiology
EDAT- 1990/05/01 00:00
MHDA- 1990/05/01 00:01
CRDT- 1990/05/01 00:00
PHST- 1990/05/01 00:00 [pubmed]
PHST- 1990/05/01 00:01 [medline]
PHST- 1990/05/01 00:00 [entrez]
AID - 10.1152/jn.1990.63.5.1089 [doi]
PST - ppublish
SO  - J Neurophysiol. 1990 May;63(5):1089-97. doi: 10.1152/jn.1990.63.5.1089.