The normal occurrence of octopamine in the central nervous system of the rat.

An enzymatic assay for octopamine capable of detecting 50 pg of amine was developed and used to study the distribution of octopamine in regions of the rat central nervous system. The presence of octopamine in the rat pineal organ was confirmed by mass spectrometry; Administration of a monoamine oxidase inhibitor and of tyramine led to increases in CNS octopamine levels while the administration of reserpine intraperitoneally or 6-hydroxydopamine intraventricularly led to decreases in octopamine levels. The results suggest that in the mammalian CNS octopamine is present in neural structures where it may be involved in synaptic function.