Metabolic Syndrome Impairs Cerebrovascular Tone and Behaviour in Obese Zucker Rats

Metabolic syndrome is associated with cerebrovascular disease and cognitive impairment. We determined vascular reactivity in middle cerebral arteries (MCA), and performed cognitive testing using an operant conditioning chamber (OCC) and Morris Water Maze (MWM). Male obese Zucker rats (OZR) were used to test the hypothesis that the pro-inflammatory environment present in the OZR impairs cerebrovascular tone regulation and is associated with neuroinflammation of the white matter and cognitive impairment. Dilation of MCA following challenge with acetylcholine was blunted, whereas constrictor responses were enhanced. Learning was impaired in the MWM and a shift in swim strategy towards increased allocentric navigation was observed. Few impairments were detected in the OCC tests or when white matter regions were examined for markers of neuroinflammation. These results suggest that the reactivity of MCA in OZR is altered with MetS, and that this impairment is associated mild cognitive dysfunction in the absence of white matter inflammation