Transient expression of calretinin in the trout habenulo-interpeduncular system during development

Abstract

Calcium-binding proteins control calcium homeostasis during neural development. The expression of one of these proteins, calretinin (CR), was monitored by immunohistochemistry in the developing habenulo-interpeduncular system of the rainbow trout, a conserved region of the brain along vertebrate phylogeny that undergoes a neurochemical reorganization in late development. No CR-immunoreactivity was observed in the habenulo-interpeduncular system during the embryonic development. CRimmunolabeling appeared in newly hatched fry, and during the fry development the number of CR-immunostained elements increased progressively. During the juvenile stages (from 30 days post-hatching onwards) a gradual decrease in the number of CRimmunostained cells occurred, until its complete disappearance in adults. These variations in CR expression may represent variable calcium-buffering needs during different developmental stages.