Neuropeptides and monoamines in the torus semicircularis of the carp (Cyprinus carpio)

The distribution of vasoactive intestinal polypeptide, gastrin-releasing peptide, gamma-melanocyte-stimulating hormone, alpha-neo-endorphin, angiotensin II, cholecystokinin-8, serotonin, and tyrosine hydroxylase has been studied in the nuclei lateralis and centralis of the Cyprinus carpio torus semicircularis using an indirect immunoperoxidase technique. In both nuclei, we found vasoactive intestinal polypeptide, gastrin-releasing peptide, gamma-melanocyte-stimulating hormone, alpha-neo-endorphin, serotonin, and tyrosine hydroxylase immunoreactive fibers, whereas the torus semicircularis was not immunoreactive for cholecystokinin-8 and angiotensin II. Moreover, no immunoreactive cell bodies containing peptides or monoamines were observed. The presence of these peptides and monoamines in both the nuclei lateralis and centralis suggests that such substances might be involved in the control of the visual, auditive, and/or lateral line information systems.