Piper R D, Lambert G A
Institute of Neurological Sciences, Prince Henry Hospital School of Medicine, University of New South Wales, Sydney, Australia.
Cephalalgia. 1996 Apr;16(2):87-92. doi: 10.1046/j.1468-2982.1996.1602087.x.
Cortical spreading depression (SD) has not been shown in the human neocortex by direct cortical recordings. However, animal studies suggest that cortical injury, such as that occurring during neurosurgical procedures, should result in the initiation of SD. It is possible that inhibition of SD by volatile anesthetic agents may partially explain the failure to observe SD in the human neocortex during surgery. This study examines the effect of the anesthetic agents alpha-chloralose, halothane, nitrous oxide and isoflurane on the initiation of cortical SD in the cat neocortex. SD was seen in 100% of cats anesthetized with alpha-chloralose (n = 15), in 3 of 7 (42%) animals anesthetized with isoflurane (p < 0.05, chi 2 with Yates correction) and none of the animals (n = 4, 6 hemispheric preparations) anesthetized with halothane (p < 0.005, chi 2 with Yates correction, halothane vs alpha-chloralose group). In all cases this inhibitory effect was reversible. In four animals the administration of nitrous oxide (66%) reduced the inspired concentration of isoflurane required to inhibit SD by 0.75%. This study suggests that halothane, and to a lesser extent isoflurane and nitrous oxide, protect against the initiation of cortical SD. This observation may partially explain why SD has not been demonstrated in human neocortex during surgery. Further studies are needed to determine if SD may occur under pathological conditions, such as during migraine with aura, where the cortex may be predisposed to SD.
通过直接皮层记录尚未在人类新皮层中显示出皮层扩散性抑制（SD）。然而，动物研究表明，皮层损伤，如神经外科手术过程中发生的损伤，应会引发SD。挥发性麻醉剂对SD的抑制作用可能部分解释了在手术过程中未能在人类新皮层中观察到SD的原因。本研究考察了麻醉剂α-氯醛糖、氟烷、氧化亚氮和异氟烷对猫新皮层中皮层SD引发的影响。在用α-氯醛糖麻醉的猫（n = 15）中，100%出现了SD；在用异氟烷麻醉的7只动物中有3只（42%）出现了SD（p < 0.05，采用Yates校正的卡方检验）；在用氟烷麻醉的动物中（n = 4，6个半球标本）均未出现SD（p < 0.005，采用Yates校正的卡方检验，氟烷组与α-氯醛糖组比较）。在所有情况下，这种抑制作用都是可逆的。在4只动物中，给予氧化亚氮（66%）使抑制SD所需的异氟烷吸入浓度降低了0.75%。本研究表明，氟烷以及程度较轻的异氟烷和氧化亚氮可防止皮层SD的引发。这一观察结果可能部分解释了为什么在手术过程中未在人类新皮层中证实SD的存在。需要进一步研究以确定在病理条件下，如在伴有先兆的偏头痛期间，皮层可能易发生SD时，SD是否会出现。
