In this study, we report that the treatment of strychinine (STR), an inhibitor of glycine receptor, induced premature onset of programmed cell death (PCD) of developing chick motoneurons (MNs). Treatment of STR on E4 chick embryo increased the apoptosis of MN on E5 when MN PCD does not occur normally. On the other hand, treatment of STR from E3 or E5 for 24 hours did not significantly influence the extent of MN PCD, indicating that the STR effect is developmental stage-specific. However, the expression of glycine receptor isoform was low on E3-4, and other glycine receptor antagonists did not exhibit PCD-promoting activity, suggesting that the STR action on PCD is not related to the glycine receptor activation. Identification of the target molecule for STR action may provide novel mechanism how the onset of developmental PCD is regulated.

Keywords: strychinine, glycine receptor, programmed cell death, chick embryo, development