Brain metabolism and spatial memory are affected by portal hypertension

Portal hypertension is a major complication of cirrhosis that frequently leads to a neuropsychiatric disorder that affects cognition. The present study was undertaken in order to compare the performance of sham-operated rats (SHAM) and portal hypertension rats (PH) in reference memory tasks in the Morris water maze (MWM). Two groups of animals were used: SHAM group (n=12) was used as a control group and PH group (n=12) by the triple portal vein ligation method was used as an animal model of early evolutive phase of PH. The portal pressure was measured in the splenic parenchyma. Our work shows that spatial learning in the MWM is not impaired in PH group although this group showed a one-day delay in the task acquisition compared to the SHAM group. We assessed the brain metabolic activity of the animals by means of cytochrome c-oxidase (COx) histochemistry. Significant changes were found in the CA3, dentate gyrus, basolateral, medial, lateral and central amygdala, showing lower COx activity in the PH group as compared to the SHAM group in all cases. We found no changes in metabolic activity in prefrontal cortex and CA1 area between groups. In fact, different neural networks were shown according to the execution level of the subjects. The early PH evolution induced changes in brain metabolic activity without biggest alterations in spatial memory.