Effects of metabolic pH-alterations on cerebral blood flow and oxygen uptake following E. coli endotoxin in dogs.
The aim of the present study was to investigate if metabolic pH-alterations have an influence on cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) after an injection of E. coli endotoxin. Following endotoxin in dogs with normal pH a decreased CBF and an increased CMRO2 have earlier been found. Thirteen anaesthetized dogs were subjected to metabolic pH-variations in blood by infusion of hydrochloric acid or sodium bicarbonate. Ten dogs received E. coli endotoxin in a dose of 1 mg.kg-1 bodyweight. CBF, CMRO2 and noradrenaline and adrenaline concentrations in blood and cerebrospinal fluid were measured repeatedly during normoxia and normocarbia. Measurements before endotoxin served as controls, together with three additional animals, where endotoxin was never given. In control measurements pH showed no influence on the variables studied. After endotoxin CBF, CMRO2 and noradrenaline in cerebrospinal fluid increased with decreasing arterial blood pH. The influence exerted by metabolic pH alterations in blood after endotoxin may be explained by hydrogen ions and monoamines passing over a blood-brain barrier (BBB), damaged by endotoxin, into the brain tissue causing vasodilation and neuronal activation.
Westerlind
A
A
Department of Anaesthesiology and Intensive Care, Sahlgren's Hospital, University of Göteborg, Sweden.
Larsson
L E
LE
Häggendal
J
J
Ekström-Jodal
B
B
D000138:Acidosis / Q000378:metabolism / Q000503:physiopathology; D000471:Alkalosis / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004285:Dogs; D004731:Endotoxins / Q000008:administration & dosage / Q000494:pharmacology*; D004837:Epinephrine / Q000097:blood; D004926:Escherichia coli; D005260:Female; D006851:Hydrochloric Acid / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000097:blood / Q000134:cerebrospinal fluid; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects*
D001639:Bicarbonates; D004731:Endotoxins; D008070:Lipopolysaccharides; D006851:Hydrochloric Acid; D010100:Oxygen; D009638:Norepinephrine; D004837:Epinephrine