Correlated basal expression of immediate early gene egr1 and tyrosine hydroxylase in zebrafish brain and downregulation in olfactory bulb after transitory olfactory deprivation

► First basal expression study of immediate early gene egr1 in the entire zebrafish brain from larval into adult stages. ► Identification of cellular co-localization sites of egr1 with tyrosine hydroxylase (dopamine) in zebrafish brain. ► New double-fluorescence in situ hybridization/immunohistochemical protocol for confocal microscopy of zebrafish tissue. ► Unilateral olfactory deprivation experiments show downregulation of TH/egr1 expressing cells in zebrafish olfactory bulb.