伤害性刺激反应对丙泊酚在犬脊髓不同区域分布的影响

Effect of noxious stimulation on regional distribution of propofol in canine spinal cord

目的观察伤害性刺激反应对丙泊酚在犬脊髓不同区域分布的影响。方法 12只12～18月健康杂种犬,雌雄不拘,体质量10～12kg,随机平均分为对照组(C组)和刺激组(S组),每组6只,均以丙泊酚7mg/kg静脉注射,续以70mg/kg·h恒速静脉输注。S组输注45min时给予钳夹刺激5min,C组不给予刺激,两组丙泊酚输注50min时取颈内动静脉血各2ml,同时断头处死实验犬,解剖犬脊髓取其前角、背角、中间带、前索、后索、外侧索组织,采用高效液相色谱法(HPLC)检测动、静脉血浆和脊髓组织丙泊酚浓度。结果颈内动、静脉血浆丙泊酚浓度C组分别为(5.09±0.03)、(5.08±0.03)μg/ml,S组分别为(5.07±0.23)、(5.03±0.10)μg/ml,两者差异无统计学意义(P>0.05);脊髓组织丙泊酚浓度(μg/g):C组前角5.09±0.08、背角5.10±0.08、中间带5.05±0.19、前索5.06±0.14、后索5.06±0.15、外侧索5.06±0.41,上述各解剖区域丙泊酚浓度差异无统计学意义(P>0.05);S组背角和后索内丙泊酚浓度分别为(7.65±0.47)、(7.06±0.82)μg/g,明显高于组内其他区域(P<0.05),也明显高于C组背角和后索(P<0.05)。结论恒速输注丙泊酚70mg/kg·h50min,动静脉血丙泊酚浓度达到平衡状态,丙泊酚在犬脊髓前角、背角、中间带、前索、后索、外侧索的分布均衡;给予伤害性刺激时,背角和后索丙泊酚浓度较高,丙泊酚在犬脊髓其他解剖区域的分布趋于均衡。

Objective To observe the regional distribution of propofol in canine spinal cord under noxious stimulation. Methods Twelve healthy hybrid dogs （12-18 months old, weighing 10-12 kg） were randomly divided into control group （n=6） and stimulation group （n=6）. All the dogs were anesthetized with a single bolus dose of propofol （7 mg/kg） in 15 seconds followed by propofol infusion at a constant rate of 70 mg·kg-1·h-1 via the great saphenous vein of the right posterior limb. In the stimulation group, the tails of the dogs were clamped for 5 min after 45 min of propofol infusion. Blood samples were taken from the internal carotid artery and internal jugular vein at 50 min after propofol infusion to detect plasma propofol concentrations by high-pressure liquid chromatography （HPLC）. The dogs were then immediately sacrificed by decapitation and the frontal horn, posterior horn, intermediate zone, frontal funiculus, posterior funiculus and lateral funiculus of the spinal cord were dissected for determination of propol content by HPLC. Results The plasma concentrations of propofol in the internal carotid artery and internal jugular vein were 5.07±0.23 and 5.03±0.10 μg/ml in the stimulation group, respectively showing no significant differences from those in the control group （5.09±0.03 and 5.08±0.03 μg/ml, P0.05）. In the control group, the propofol concentration was 5.09±0.08 μg/g in the frontal horm, 5.10±0.08 μg/g in the posterior horn, 5.05±0.19 μg/g in the intermediate zone, 5.06±0.14 μg/g in the frontal funiculus, 5.06±0.15 μg/g in the posterior funiculus and 5.06± 0.41 μg/g in the lateral funiculus, showing no significant differences （P0.05）. The propofol concentrations in the frontal horn （7.65±0.47 μg/g） and posterior funiculus （7.06±0.82 μg/g） in the stimulation group were significantly higher than those in the other spinal cord tissues （P0.05） and those in the control group （P0.05）. Conclusion At 50 min after intravenous injection of propofol at a constant rate of 70 mg·kg-1·h-1, plasma propofol concentrations in the internal carotid artery and internal jugular vein reaches equilibrium with a balanced distribution in all the spinal cord regions. Propofol concentration can be higher in the frontal horn and posterior funiculus under noxious stimulation.