Brain-derived neurotrophic factor in human saliva: ELISA optimization and biological correlates.

In order to assess the physiological significance of human salivary brain-derived neurotrophic factor (BDNF), we have optimized a sensitive and specific enzyme-linked immunosorbent assay (ELISA). We determined the range of salivary BDNF concentrations, the impact of saliva collection method, and the association of salivary BDNF with several biological characteristics. The ELISA had a detection limit of 62.5 pg/mL, and intra-assay and interassay precisions of 4.2% and 8.2%, respectively. Salivary BDNF concentrations were highly variable between individuals (median = 618 pg/mL) and were affected by collection method. Women had significantly higher levels of salivary BDNF than men. There was no relationship, however, between salivary BDNF levels and the other biological characteristics examined.