High correlation between salivary MHPG and CSF MHPG

Rationale: Determination of 3-methoxy-4-hydroxy-phenylglycol (MHPG) as a major metabolite of noradrenaline may reflect changes in noradrenergic activity dependent on psychiatric illness and drug therapy. Objective: This study was designed to investigate the relationship between CSF and salivary MHPG, and thus the utility of saliva MHPG as a marker for CSF MHPG. Method: Twenty-one paired samples of saliva and CSF were assayed for MHPG by solid-phase extraction and HPLC-ED. Result: Salivary MHPG was highly positively correlated with CSF MHPG (P<0.001). Conclusion: This finding supports the use of salivary MHPG as an index for CSF MHPG, and enhances the usefulness of salivary MHPG measurements as a non-invasive approach for clinical studies investigating noradrenergic systems.