Hemodynamic characteristics in neural crest cell-excised chick embryo.

Damage to premigratory cranial neural crest cells results in cardiovascular anomalies of so-called conotruncal anomaly. In one report, it was suggested that hemodynamic alteration would precede abnormal cardiovascular morphogenesis. We repeated this hemodynamic study in neural crest cell-excised chick embryos and found that there was no difference in heart rate and blood pressure between the treated embryos (n = 11; 164 +/- 3 beats per min (BPM) and 0.75 +/- 0.03 mmHg, respectively) and control embryos (n = 7; 160 +/- 6 BPM and 0.72 +/- 0.07 mmHg, respectively). The response of heart rate to acetylcholine was less (P less than 0.05) in the treated embryos (-13% +/- 2%) than in the control (-20% +/- 2%). Thus, the present data do not support the hypothesis that alterations in blood pressure and heart rate are causally related to abnormal cardiovascular morphogenesis. The developmental significance of subtle functional changes in neural crest-extirpated embryos in response to cholinergic challenge is unclear.