Samoilov M O, Semenov D G, Tulkova E I, Lazarewicz J W
Pavlov Institute of Physiology, Russian/St. Petersburg Academy of Sciences.
Resuscitation. 1992 Feb;23(1):33-43. doi: 10.1016/0300-9572(92)90160-e.
We studied the changes in the content of membrane-bound calcium (Cab) and the polyphosphoinositides (poly-PI): bis- and trisphosphoinositide (PIP and PIP2) in the cat brain cortex during the early period (up to 30 min) of reoxygenation after 2.5 min and 5 min of anoxia. In vivo experiments were performed on a living cat cortical preparation. Studies included Cab estimation with clortetracycline, a calcium fluorescent chelate probe, and simultaneous registration of neuronal activity. Anoxia resulted in a significant drop of Cab and PIP2 in the cortex along with an absence of neuronal activity. During reoxygenation after 2.5 min of anoxia we observed an increase of Cab, however the Cab did not recover to the preanoxic level. An elevation of PIP and PIP2 content to 20% above the preanoxic level and recovery of neuronal activity with symptoms of hyperactivation were also observed. After 5 min of anoxia two qualitatively different types of changes were disclosed for the 30 min period of reoxygenation. In one half of the animals only slight symptoms of recovery in some of the indices were found. In the other group Cab and PIP2 content increased to a level significantly exceedingly the preanoxic one and abnormal spike activity appeared. Based on these results we suggest that disturbances in Ca- and poly-PI-related second messenger systems may significantly affect the recovery of neuronal function after anoxia.
我们研究了猫脑皮层在缺氧2.5分钟和5分钟后复氧早期（长达30分钟）膜结合钙（Cab）和多磷酸肌醇（多聚-PI）：双磷酸肌醇和三磷酸肌醇（PIP和PIP2）含量的变化。在活猫皮层制备物上进行体内实验。研究包括用钙荧光螯合探针氯四环素估计Cab，并同时记录神经元活动。缺氧导致皮层中Cab和PIP2显著下降，同时神经元活动消失。在缺氧2.5分钟后的复氧过程中，我们观察到Cab增加，然而Cab并未恢复到缺氧前水平。还观察到PIP和PIP2含量升高至比缺氧前水平高20%，并且神经元活动恢复并伴有过度激活症状。缺氧5分钟后，在复氧的30分钟期间发现了两种性质不同的变化类型。在一半的动物中，仅在某些指标中发现了轻微的恢复症状。在另一组中，Cab和PIP2含量增加到显著超过缺氧前水平，并且出现了异常的尖峰活动。基于这些结果，我们认为钙和多聚-PI相关的第二信使系统的紊乱可能会显著影响缺氧后神经元功能的恢复。
