Purine and monoamine metabolites in cerebrospinal fluid: parallel purinergic and monoaminergic activation in depressive illness?

In the cerebrospinal fluid of 38 patients with major depressive disorders the purine metabolites hypoxanthine and xanthine were positively correlated to the monoamine metabolites HVA and 5HIAA (p less than 0.0001). Hypoxanthine was also positively linked to the noradrenaline metabolite MHPG (p less than 0.005). By the use of multiple regression analysis 70% of the variance in hypoxanthine and 51% of the variance in xanthine were explained by HVA and 5HIAA. The scored magnitude of memory disturbance during depression was positively correlated to hypoxanthine, xanthine, HVA, and 5HIAA, while the degree of somatic anxiety as well as worrying was or tended to be negatively correlated to the same biochemical markers. The conspicuous relationship observed between purine and monoamine metabolite concentrations in CSF during depressive illness might indicate a parallel purinergic and monoaminergic activation of the brain. The observation that certain isolated depressive symptoms appear to relate to hypoxanthine/xanthine in CSF is consistent with the hypothesis of a central role of purines in behaviour.