Exploring Octopamine: Immunohistochemical research of a spionid worm <em>Pygospio elegans</em> nervous system

Abstract

Octopamine is a biogenic amine specific for invertebrates distributed in all groups from Cnidaria to Echinodermata. Our study is aimed to investigate the octopamine-positive elements in the nervous system of the spionid worm Pygospio elegans. Immunohistochemistry was used to detect octopamine-positive elements in the central and peripheral nervous systems. While the central nervous system exhibited weak staining, the peripheral nervous system showed specifically octopamine-like elements in the palps, peristomium, and body segments. The detected octopamine-like elements were compared with other neurotransmitters in the P. elegans nervous system. Our results contribute to the data on annelid octopaminergic nervous system structure.