Tyrosine hydroxylase immunoreactivity in a subpopulation of granule cells in the olfactory bulb of teleost fish

Abstract

The distribution of tyrosine hydroxylase (TH)-like immunoreactivity in the olfactory bulb was studied in three species of teleosts, the tench Tinca tinca, the Mediterranean barbel Barbus meridionalis and the rainbow trout Salmo gairdneri, by using an indirect immunoperoxidase method. The antiserum used displayed a characteristic pattern of immunostaining in the three species, and four main conclusions can be drawn: (1) there is a large population of TH-like positive cell bodies and fibers in the olfactory bulb in fish, mainly in the granule cell and plexiform layers; (2) the immunolabeled cells are identified as granule cells, but only one group of granule cells is positive; (3) specific quantitative variations exist in the pattern of TH immunoreactivity, with use of the same fixative, antibody and localization method, among the three species studied, and (4) the pattern of TH immunoreactivity in the olfactory bulb in teleosts is completely different from that described previously in amniotes.