Cerebral non-oxidative carbohydrate consumption in humans driven by adrenaline.
During brain activation, the decrease in the ratio between cerebral oxygen and carbohydrate uptake (6 O(2)/(glucose + (1)/(2) lactate); the oxygen-carbohydrate index, OCI) is attenuated by the non-selective beta-adrenergic receptor antagonist propranolol, whereas OCI remains unaffected by the beta(1)-adrenergic receptor antagonist metroprolol. These observations suggest involvement of a beta(2)-adrenergic mechanism in non-oxidative metabolism for the brain. Therefore, we evaluated the effect of adrenaline (0.08 microg kg(-1) min(-1) i.v. for 15 min) and noradrenaline (0.5, 0.1 and 0.15 microg kg(-1) min(-1) i.v. for 20 min) on the arterial to internal jugular venous concentration differences (a-v diff) of O(2), glucose and lactate in healthy humans. Adrenaline (n = 10) increased the arterial concentrations of O(2), glucose and lactate (P < 0.05) and also increased the a-v diff for glucose from 0.6 +/- 0.1 to 0.8 +/- 0.2 mM (mean +/- s.d.; P < 0.05). The a-v diff for lactate shifted from a net cerebral release to an uptake and OCI was lowered from 5.1 +/- 1.5 to 3.6 +/- 0.4 (P < 0.05) indicating an 8-fold increase in the rate of non-oxidative carbohydrate uptake during adrenaline infusion (P < 0.01). Conversely, noradrenaline (n = 8) did not affect the OCI despite an increase in the a-v diff for glucose (P < 0.05). These results support that non-oxidative carbohydrate consumption for the brain is driven by a beta(2)-adrenergic mechanism, giving neurons an abundant provision of energy when plasma adrenaline increases.
Seifert
Thomas S
TS
Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Denmark. tseifert78@gmail.com
Brassard
Patrice
P
Jørgensen
Thomas B
TB
Hamada
Ahmad J
AJ
Rasmussen
Peter
P
Quistorff
Bjørn
B
Secher
Niels H
NH
Nielsen
Henning B
HB
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000378:metabolism*; D050260:Carbohydrate Metabolism / Q000187:drug effects*; D004837:Epinephrine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D019344:Lactic Acid / Q000097:blood; D008297:Male; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000097:blood; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism; D055815:Young Adult
D001786:Blood Glucose; D018343:Receptors, Adrenergic, beta-2; D019344:Lactic Acid; D010100:Oxygen; D009638:Norepinephrine; D004837:Epinephrine