First characterization of 5-hydroxytryptophan in rat brain by using specific antibodies

DL-5-Hydroxytryptophan (5-HTP) was conjugated to bovine serum albumin and human serum albumin with glutaraldehyde (G). These conjugates made it possible to raise specific antisera in two rabbits. Their specificity and affinity were evaluated using an enzyme-linked immunosorbent assay and immunocytochemistry. For two antisera obtained, the most immunoreactive antigen was 5-HTP-G-protein, indicating that the same immune response was developed. The other conjugated indoleamines (5-methoxytryptophan-G-protein, tryptophan-G-protein) were poorly recognized or not at all (5-methoxytryptamine-G-protein, serotonin-G-protein, tryptamine-G-protein). These 5-HTP antisera enabled us to specifically visualize the precursor of serotonin in the raphe nuclei of G-fixed rat brains.