Effect of pre-ischaemic conditioning on hypoxic depolarization of dopamine efflux in the rat caudate brain slice measured in real-time with fast cyclic voltammetry

• Published in: Neurochemistry international 2011-10, Vol.59 (5), p.714-721
• Main Authors: Davidson, Colin, Coomber, Ben, Gibson, Claire L., Young, Andrew M.J.
• Format: Article
• Language: English
• Subjects: 3,4-Dihydroxyphenylacetic Acid - metabolism; Analysis of Variance; Animals; Biological and medical sciences; Brain-slice; Caudate Nucleus - metabolism; Chromatography, High Pressure Liquid; Conditioning; Dopamine; Dopamine - metabolism; Electrochemistry; Fundamental and applied biological sciences. Psychology; Glucose - deficiency; HPLC; Hypoxia, Brain - metabolism; In Vitro Techniques; Ischaemia; Ischemic Preconditioning; Male; Rats; Rats, Wistar; Vertebrates: nervous system and sense organs; Voltammetry
• ISSN: 0197-0186; 1872-9754
• DOI: 10.1016/j.neuint.2011.06.020

► We describe pre-ischaemic conditioning in the rat caudate for the first time. ► We show that ischemia-evoked dopamine efflux can be used to measure conditioning. ► We use fast cyclic voltammetry to measure dopamine release in response to ischaemia in real time. ► We show that 10 but not 2min of pre-ischaemic conditioning evoked tolerance to a second ischaemic event. Fast cyclic voltammetry can be used to measure dopamine release after oxygen and glucose deprivation (OGD) induced anoxic depolarization in vitro. Here we measure dopamine efflux with 1s time resolution, which is appropriate to measure OGD-evoked dopamine efflux accurately. In the present study, we examined whether OGD-evoked dopamine efflux could be used to show pre-ischaemic conditioning in the rat caudate brain slice. Caudate slices were exposed to 0, 2, or 10min OGD pre-ischaemic conditioning, then 60min later exposed to a second OGD event of 15min duration. We measured the OGD-evoked dopamine efflux using fast cyclic voltammetry and in some experiments caudate dopamine and DOPAC tissue levels were measured using HPLC and 20μm cryostat sections were Nissl stained to indicate neuronal loss. We found that 10 but not 2min OGD pre-ischaemic conditioning resulted in a longer time to onset of OGD-evoked dopamine efflux on the main OGD event (475±31 and 287±30s for 10 Vs 0min pre-ischaemic conditioning respectively). Further, 10min OGD pre-ischaemic conditioning resulted in less dopamine efflux on the second OGD event (4.23±1.12 and 8.14±0.82μM for 10 Vs 0min pre-ischaemic conditioning respectively), despite these slices having similar tissue dopamine content and DOPAC/DA ratio, and the rate of dopamine release was slower in the main OGD event (21±5 and 74±8nM/s for 10 Vs 0min pre-ischaemic conditioning respectively). These data suggest that 10min OGD pre-ischaemic conditioning can evoke tolerance to a second OGD event and that voltammetric recording of OGD-evoked dopamine efflux is a useful model of pre-ischaemic conditioning in neuronal tissue.