Hydrogen Ion Variations and Their Interpretation in the Microenvironment of the Vertebrate Brain
The introduction  of a reliable liquid membrane ion-selective micropipette (ISM) for H+ has opened up an important new window onto ion and metabolic homeostasis in brain tissue. Formerly, glass membrane ISMs were commonly used , but frequently the response was too slow to capture H+ transients. They were also difficult to fabricate as double-barrelled electrodes, i. e., with an integral reference barrel . An alternative type of ISM for H+ employed antimony as the sensor and has been variously configured (e.g., ). This sensor, however, is subject to a variety of ill-defined interferences . The liquid membrane ISM overcomes virtually all the deficiencies of previous sensors (note, however, that dinitrophenol and presumably other lipophilic proton transporting anions, destabilize the ISM). We have made an extensive study of pH changes in the cerebellar microenvironment of the in vivo rat . More recently, we have studied the microenvironment of the in vitro turtle cerebellum. We shall draw on both these studies here.
KeywordsLiquid Membrane Spreading Depression Neutral Carrier Brain Microenvironment Previous Sensor
Unable to display preview. Download preview PDF.
- 5.Lehmenkühler A, Zidek W, Staschen M, Caspers H (1981) Cortical pH and pCa in relation to DC potential shifts during spreading depression and asphyxiation. In: Syková E, Hńik P, Vyklickč L (eds) Ion-selective microelectrodes and their use in excitable tissues. Plenum, New York, pp 225–229Google Scholar
- 7.Nicholson C, Kraig RP (1981) The behavior of extracellular ions during spreading depression. In: Zeuthen T (ed) The application of ion-selective microelectrodes. Elsevier/North Holland, New York, pp 217–238Google Scholar
- 8.Nicholson C, Phillips JM (1981) Ion diffusion modified by tortuosity and volume fraction in the extracellular microenvironment of the rat cerebellum. J Physiol (Lond) 321: 225–257Google Scholar
- 9.Nicholson C, Phillips JM, Tobias C, Kraig RP (1981) Extracellular potassium, calcium and volume profiles during spreading depression. In: Syková E, Hńik P, Vyklickč L (eds) Ion-selective microelectrodes and their use in excitable tissues. Plenum, New York, pp 225–229Google Scholar
- 12.Siesjö BK (1978) Brain energy metabolism. Wiley, New YorkGoogle Scholar
- 13.Stewart PA (1981) How to understand acid-base. Elsevier, New YorkGoogle Scholar
- 14.Thomas RC (1978) Ion-selective intracellular microelectrodes. Academic, New YorkGoogle Scholar