Hypothalamo-neurohypophysial neurons in vitro: developmental potentials depend on the donor rat stock.

Primary dispersed cell cultures were established from fetal diencephalic tissue derived from two stocks of outbred rats. The overall growth pattern, as followed by phase-contrast microscopy and visualized by immunocytochemistry for neurofilament proteins and neuron specific enolase, depended on the age of the donor animal. Stock differences were not revealed by these methods. In contrast, when the cultures were immunostained in order to assess the yield of a specific type of cell, i.e., magnocellular hypothalamic neurons, striking differences were observed between the two stocks of rats. Whereas neurophysin-immunoreactive cells could be grown in cultures established from fetal Chbb: Thom rats at embryonic days 14, 15, and 18, no such cells could be detected in cultures derived from Crl: CD (SD) BR rats older than embryonic day 14. These findings may reflect differences in the differentiation schedule and/or requirements for certain epigenetic and trophic factors between magnocellular neuroblasts derived from the two stocks of rats.