Brain microdialysis in exercise research

• Published in: Sports medicine (Auckland) 2001, Vol.31 (14), p.965-983
• Main Authors: MEEUSEN, Romain, PIACENTINI, M. Francesca, DE MEIRLEIR, Kenny
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Brain - metabolism; Brain Chemistry - physiology; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Exercise - physiology; Extracellular Space - chemistry; Fundamental and applied biological sciences. Psychology; Humans; microdialysis; Microdialysis - methods; Neurotransmitter Agents - metabolism; Physical Conditioning, Animal - physiology; Physical Conditioning, Animal - psychology; Vertebrates: nervous system and sense organs
• ISSN: 0112-1642; 1179-2035
• DOI: 10.2165/00007256-200131140-00002

During the last 5 to 10 years, the microdialysis technique has been used to explore neurotransmitter release during exercise. Microdialysis can collect virtually any substance from the brains of freely moving animals with a limited amount of tissue trauma. It allows the measurement of local neurotransmitter release in combination with ongoing behavioural changes such as exercise. Several groups examined the effect of treadmill running on extracellular neurotransmitter levels. Microdialysis probes were implanted in different brain areas to monitor diverse aspects of locomotion (striatum, hippocampus, nucleus accumbens, frontal cortex, spinal cord), food reward (hypothalamus, hippocampus, cerebral cortex), thermoregulation (hypothalamus). Some studies combined microdialysis with running on a treadmill to evaluate motor deficit and improvement following dopaminergic grafts in 6-hydroxydopamine lesioned rats, or combined proton nuclear magnetic resonance spectroscopy and cortical microdialysis to observe intra- plus extracellular brain glucose variations. This method allows us to understand neurotransmitter systems underlying normal physiological function and behaviour. Because of the growing interest in exercise and brain functioning, it should be possible to investigate increasingly subtle behavioural and physiological changes within the central nervous system. There is now compelling evidence that regular physical activity is associated with significant physiological, psychological and social benefits in the general population. In contrast with our knowledge about the peripheral adaptations to exercise, studies relating exercise to brain neurotransmitter levels are scarce. It is of interest to examine the effect of short and long term exercise on neurotransmitter release, since movement initiation and control of locomotion have been shown to be related to striatal neurotransmitter function, and one of the possible therapeutic modalities in movement, and mental disorders is exercise therapy. Until very recently most experimental studies on brain chemistry were conducted with postmortem tissue. However, in part because of shortcomings with postmortem methods, and in part because of the desire to be able to directly relate neurochemistry to behaviour, there has been considerable interest in the development of 'in vivo' neurochemical methods. Because total tissue levels may easily mask small but important neurochemical changes related to activity, it is importa