Abstract
The hemodynamic changes in septic patients produced by inhalational anesthetics are sufficient to threaten the anesthesiologists. The effect of hydroxocobalamin, a vitamin $B_{12a}$, on contractile responses to phenylephrine during administration of inhalational anesthetics were evaluated in aortic ring preparations obtained from LPS-treated rats. The sepsis was developed by intraperitoneal injection of LPS (1.5 mg/kg for l8h) and confirmed by iNOS expression using RT-PCR. Statistical significances (P<0.05) were analyzed by Student's t-test or paired t-test according to data characteristics. The blood pressure, but not heart rate, was decreased in LPS-treated rats as compared to control rats. The contractile response to phenylephrine were dose-dependently increased from the doses of $10^{-8}\;M$ to that of $10^{-5}$ and were attenuated in LPS-treated rings. Both halothane and enflurane, at the doses of 1 MAC, decreased the contractile responses to phenylephrine while isoflurane did not significantly affect the contractile responses. Hydroxocobalamin ($10^{-5}$ M) significantly potentiated the contractile responses in the LPS-treated aortic ring preparations during administration of each inhalational anesthetic or not. From these results, it is suggested that hydroxocobalamin may improve the hemodynamics of septic patients during inhalational anesthesia. Abbreviations: LPS, lipopolysaccharide; RT-PCR, reverse transcription-polymerase chain reaction; MAC, minimum alveolar concentration; iNOS, inducible nitric oxide synthase; GAPDH, glyceraldehyde 3-phosphate dehydrogenase
패혈증 환자에 흡입마취제를 투여하는 것은 혈역동학에 심각한 영향을 초래할 수 있다. 흡입마취제 투여시 내독소혈증흰쥐 대동맥 수축반응에 미치는 hydroxocobalamin의 영향을 알아보기위해, 내독소 (1.5 mg/kg)를 복강내 투여한 뒤 18시간 후에 대동맥을 적출하여 phenylephrine에 대한 수축반응과 이에 대한 흡입마취제 및 hydroxocobalamin의 작용을 알아보았다. 패혈증이 적절히 유발되었는 지를 확인하기 위해 RT-PCR을 이용하여 혈관 평활근에서 iNOS유도를 확인하였다. 내독소 처치에 의해 수축기 및 확장기 혈압이 대조군에 비해 유의하게 감소되었으나, 심박동수는 영향이 없었다. Phenylephrine에 대한 수축반응은 $10^{-8}\;M$부터 $10^{-5}\;M$까지 용량 의존적으로 증가했으며, 내독소혈증흰쥐 대동맥에서 수축반응이 억제되었다. halothane과 enflurane은 1 MAC 농도에서 phenylephrine에 의한 수축반응을 유의하게 억제했으나 isoflurane은 영향이 없었다. Hydroxocobalamin $(10^{-5}\;M)$은 흡입마취제의 종류 및 투여 유무에 관계없이 내독소혈증흰쥐 대동맥 수축반응을 증가시켰다. 이상의 결과로 미루어보아 hydroxocobalamin은 패혈증 환자의 흡입마취시 혈역동을 개선시킬 것으로 사료된다.