By contrast, in the absence of blood circulation, tissue PO2 in vitro decreases more markedly and recovers slowly to baseline without overshooting.

• 相反的，离体脑组织没有血液循环，神经元兴奋时局部氧分压通常出现更为显著的下降，而后缓慢恢复到基线水平，不出现超射。