PTHrP mRNA was persistently expressed before and after the time of commitment of granule neurons to apoptosis when they are cultured in the presence of 25 mMKCl or both 150 uM N-methyl-D-aspartic acid and 15 mMKCl, both of which promote the survival of these neurons. [...]  The addition of anti-PTHrP antiserum to the culture medium resulted in a reduction of the activity-dependent survival of the granule neurons.;PTHrP-null embryonic mixed cerebral cortical cultures were more sensitive to kainic acid than control cultures, and PTHrP addition was found to be protective against kainate toxicity in both PTHrP-null and control cultures.