Caffeine restores regional brain activation in acute hypoglycaemia in healthy volunteers

• Published in: Diabetic medicine Vol. 24; no. 7; pp. 720 - 727
• Main Authors: Rosenthal, M. J., Smith, D., Yaguez, L., Giampietro, V., Kerr, D., Bullmore, E., Brammer, M., Williams, S. C. R., Amiel, S. A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.07.2007; Blackwell
• Subjects: Adult; Biological and medical sciences; Brain - drug effects; Brain - metabolism; Caffeine - pharmacology; Central Nervous System Stimulants - pharmacology; Cognition - drug effects; cognitive function; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; functional magnetic resonance imaging; Humans; hypoglycaemia; Hypoglycemia - physiopathology; Magnetic Resonance Imaging - methods; Male; Medical sciences; reaction time; Reaction Time - drug effects; Type 1 diabetes mellitus; Endocrinopathy; Performance evaluation; Brain; Pancreatic hormone; Methodology; Psychotropic; Volunteer; Central nervous system; Right; Activation; Regional; Encephalon; Respiratory analeptic; Choice reaction time; Xanthine derivatives; Caffeine; Type 1 diabetes mellitus; Human; cognitive function; Immunopathology; Task complexity; CNS stimulant; hypoglycaemia; Acute; Metabolic diseases; Method; Catecholamine; Hypoglycemia; Nuclear magnetic resonance imaging; Type 1 diabetes; Neurotransmitter; Medical imagery; reaction time; Performance; functional magnetic resonance imaging; Functional imaging
• ISSN: 0742-3071; 1464-5491
• DOI: 10.1111/j.1464-5491.2007.02131.x

Aims  Caffeine enhances counterregulatory responses to acute hypoglycaemia. Our aim was to explore its effects on cortical function, which are not known at present. Methods  Regional brain activation during performance of the four‐choice reaction time (4CRT) at different levels of complexity was measured using functional magnetic resonance imaging (fMRI) at euglycaemia (5 mmol/l) and hypoglycaemia (2.6 mmol/l) in the presence and absence of caffeine in six healthy right‐handed men. Results  During hypoglycaemia, caffeine enhanced adrenaline responses to hypoglycaemia (2.5 ± 0.7 nmol/l to 4.0 ± 1.0 nmol/l, P = 0.01) and restored the brain activation response to the non‐cued 4CRT, the linear increases in regional brain activation associated with increased task complexity and the ability to respond to a cue that were lost in hypoglycaemia alone. Conclusions  Caffeine can sustain regional brain activation patterns lost in acute hypoglycaemia, with some restoration of cortical function and enhanced adrenaline responsiveness. A methodology has been established that may help in the development of therapies to protect against severe hypoglycaemia in insulin therapy for patients with diabetes and problematic hypoglycaemia.