The measurement of extracellular inorganic phosphate gives a more reliable indication for severe impairment of cerebral cell function and cell death than the measurement of extracellular lactate.
The measurement of cerebral extracellular lactate levels has been suggested to be used to monitor cerebral function in intensive care However, although an increase of extracellular lactate levels is a sensitive parameter for increased cellular activity in general, it will be shown that its prognostic value is limited in regard to the severity of the impairment of cellular function. As an alternative the measurement of the extracellular levels of inorganic phosphate (IP) or adenosine is proposed here: Whereas extracellular lactate levels increased rapidly to about the same extents during ischemia (IS) and spreading depression (SD), IP rose during IS only. Adenosine, on the other hand, increased during both events to a different degree. If, therefore, lactate was the only parameter to be monitored after a cerebral insult, the results would not allow to discriminate between a transient, spontaneously recovering event as a SD and a long lasting or an irreversible loss of cell function as in persisting ischemia/hypoxia. The measurement of IP, therefore, seems to be more suitable than that of lactate or adenosine since IP will appear within the extracellular space only after a sustained failure of membrane function. Thus, the measurement of IP changes turned out to be the more useful parameter for intensive care supervision.
Scheller
D
D
Janssen Research Foundation, Neuss, Federal Republic of Germany.
Kolb
J
J
Peters
U
U
Tegtmeier
F
F
D000241:Adenosine / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000166:cytology / Q000502:physiology*; D016923:Cell Death; D005110:Extracellular Space / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D009474:Neurons / Q000502:physiology*; D009994:Osmolar Concentration; D010710:Phosphates / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D010710:Phosphates; D019344:Lactic Acid; D000241:Adenosine