Ann-Katrin Kraeuter1,2, Tadiwa Mashavave1,2, Aditya Suvarna1,2, Maarten van den Buuse2,3, Zoltán Sarnyai4,5. 1. Laboratory of Psychiatric Neuroscience, Australian Institute of Tropical Health and Medicine, Douglas, Australia. 2. College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia. 3. School of Psychology and Public Health, La Trobe University, Bundoora, Melbourne, Australia. 4. Laboratory of Psychiatric Neuroscience, Australian Institute of Tropical Health and Medicine, Douglas, Australia. zoltan.sarnyai@jcu.edu.au. 5. College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia. zoltan.sarnyai@jcu.edu.au.
Abstract
RATIONALE: Impaired cerebral glucose metabolism is a core pathological feature of schizophrenia. We recently demonstrated that a ketogenic diet, causing a shift from glycolysis to ketosis, normalized schizophrenia-like behaviours in an acute N-methyl-D-aspartate (NMDA) receptor antagonist model of the illness. Ketogenic diet produces the ketone body, β-hydroxybutyrate (BHB), which may serve as an alternative fuel source in its own right without a strict dietary regime. OBJECTIVE: We hypothesized that chronic administration of BHB replicates the therapeutic effects of ketogenic diet in an acute NMDA receptor hypofunction model of schizophrenia in mice. METHODS: C57Bl/6 mice were either treated with acute doses of 2 mmol/kg, 10 mmol/kg, or 20 mmol/kg BHB or received daily intraperitoneal injections of 2 mmol/kg BHB or saline for 3 weeks. Behavioural testing assessed the effect of acute challenge with 0.2 mg/kg MK-801 or saline on open field behaviour, social interaction, and prepulse inhibition of startle (PPI). RESULTS: Acute BHB administration dose-dependently increased BHB plasma levels, whereas the 2 mmol/kg dose increased plasma glucose levels. The highest acute dose of BHB supressed spontaneous locomotor activity, MK-801-induced locomotor hyperactivity and MK-801-induced disruption of PPI. Chronic BHB treatment normalized MK-801-induced hyperlocomotion, reduction of sociability, and disruption of PPI. CONCLUSION: In conclusion, BHB may present a novel treatment option for patients with schizophrenia by providing an alternative fuel source to normalize impaired glucose metabolism in the brain.
RATIONALE: Impaired cerebral glucose metabolism is a core pathological feature of schizophrenia. We recently demonstrated that a ketogenic diet, causing a shift from glycolysis to ketosis, normalized schizophrenia-like behaviours in an acute N-methyl-D-aspartate (NMDA) receptor antagonist model of the illness. Ketogenic diet produces the ketone body, β-hydroxybutyrate (BHB), which may serve as an alternative fuel source in its own right without a strict dietary regime. OBJECTIVE: We hypothesized that chronic administration of BHB replicates the therapeutic effects of ketogenic diet in an acute NMDA receptor hypofunction model of schizophrenia in mice. METHODS: C57Bl/6 mice were either treated with acute doses of 2 mmol/kg, 10 mmol/kg, or 20 mmol/kg BHB or received daily intraperitoneal injections of 2 mmol/kg BHB or saline for 3 weeks. Behavioural testing assessed the effect of acute challenge with 0.2 mg/kg MK-801 or saline on open field behaviour, social interaction, and prepulse inhibition of startle (PPI). RESULTS: Acute BHB administration dose-dependently increased BHB plasma levels, whereas the 2 mmol/kg dose increased plasma glucose levels. The highest acute dose of BHB supressed spontaneous locomotor activity, MK-801-induced locomotor hyperactivity and MK-801-induced disruption of PPI. Chronic BHB treatment normalized MK-801-induced hyperlocomotion, reduction of sociability, and disruption of PPI. CONCLUSION: In conclusion, BHB may present a novel treatment option for patients with schizophrenia by providing an alternative fuel source to normalize impaired glucose metabolism in the brain.