ONTOGENY OF CALRETININ EXPRESSION IN RAT DORSAL-ROOT GANGLIA

The relationship between the expression of calretinin and the maturati on level of peripheral sensory neurons was investigated by means of im munohistochemistry and immunoblot analysis. Our immunohistochemical re sults show that calretinin is expressed during two different developme ntal phases in rat dorsal root ganglia. The early phase lasts between embryonic days 11 and 14, when calretinin is detectable in the majorit y (75%) of the cells. A second phase starts at embryonic day 17 and la sts throughout the whole postnatal life, when calretinin is expressed only in a small proportion of the neurons (less than 8%). Between thes e two periods no calretinin is found in the ganglia. These changes in calretinin expression during embryonic development were confirmed by W estern blot analysis. The early expression of calretinin in dorsal roo t ganglion cells suggests that calretinin may act as a calcium regulat or until neurotrophins take over the precise tuning of intracellular c alcium concentration. (C) 1998 Elsevier Science B.V.