Fig. 4

The ³¹P MRS-detectable energy status of brain parenchyma following IL-1β challenge. a Histogram showing the mean PCr to γATP ratio (error bars indicate a 1 SD) within the ipsilateral and contralateral striatum of IL-1β-injected (1 ng/μl) animals (n = 4) and the ipsilateral striatum of vehicle- (saline) injected animals (n = 3) at 6 h. b Histogram showing the mean PCr to γATP ratio (error bars indicate a 1 SD) within the ipsilateral and contralateral striatum of IL-1β-injected (100 ng/μl) animals and the ipsilateral striatum of vehicle- (saline) injected animals. ³¹P MRS data was not obtained for the contralateral hemisphere at 6 h as this would have prolonged the extensive (10 h) protocol on day 1 of imaging by a further 1.5 h. Maintaining the animal under anaesthesia for long periods risks death and changes in energy metabolism were not expected to be observed in the contralateral hemisphere at this time point. IL-1β-injected animals: n = 6 at 2.5 h, n = 5 at 6 h, n = 6 at 24 h, n = 4 at 72 h for the ipsilateral hemisphere and n = 5 at 2.5 h, n = 4 at 24 h and n = 5 at 72 h for the contralateral hemisphere. Vehicle- (saline) injected animals: n = 3 at each time point