K+-permeability of the blood-brain barrier, investigated by aid of a K+-sensitive microelectrode.
The K+-permeability of the blood-brain barrier at the capillary level was estimated from determinations of brain extracellular K+-concentration in response to an isotonic bolus containing KCl injected into the carotid artery. A very low permeability appeared from the fact that the extracellular K+-concentration--measured by aid of K+-sensitive microelectrodes--remained unchanged during the passage of the bolus. An upper limit for the blood-brain barrier K+-permeability in the rat was estimated to be 2.8 X 10(-7) cm. with s-1.
D000818:Animals; D001812:Blood-Brain Barrier; D001923:Brain Chemistry; D005110:Extracellular Space / Q000032:analysis; D007269:Injections, Intra-Arterial; D008297:Male; D008643:Mesentery / Q000378:metabolism; D008839:Microelectrodes; D009132:Muscles / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D011189:Potassium Chloride / Q000008:administration & dosage; D051381:Rats
D011189:Potassium Chloride; D011188:Potassium