脑摄取平衡时伤害性刺激条件下异丙酚在犬脑各解剖区域的分布

Distribution of Propofol in different anatomic region of dog brain under the conditions of noxious stimuli with the brain uptake equilibrium

目的观察颈内动脉和静脉血药浓度平衡时刺激条件下异丙酚在犬脑各解剖区域的摄取和分布特征。方法12只12-18月健康杂种犬,雌雄兼用,体质量10-12 kg,随机分为刺激组和对照组,2组犬均予异丙酚7 mg.kg^-1静脉注射,续以70 mg.kg^-1.h^-1恒速静脉滴注。滴注50 min时刺激组给予钳夹刺激犬尾正中1 min,对照组不给予刺激,2组输注51 min时取颈内动脉和颈内静脉血各2 mL,同时断头处死实验犬,解剖犬脑取背侧丘脑、上丘脑、后丘脑、下丘脑、底丘脑、额叶、顶叶、颞叶、海马、扣带回、小脑、中脑、桥脑、延髓、颈髓组织。采用高效液相色谱-紫外法（HPLC）检测动静脉血浆和脑组织异丙酚浓度。结果刺激组颈内动、静脉血浆异丙酚浓度分别为（6.16±1.04）μg.g^-1和（6.16±0.49）μg.g^-1,二者比较差异无统计学意义（P〉0.05）;脑组织背侧丘脑和底丘脑异丙酚浓度明显高于其他脑组织浓度（P〈0.05）,其余不同脑组织异丙酚浓度差异无统计学意义（P〉0.05）。对照组颈内动、静脉血浆异丙酚浓度分别为（6.17±1.00）μg.g^-1和（6.16±0.96）μg.g^-1,二者比较差异无统计学意义（P〉0.05）;对照组各脑组织异丙酚浓度差异无统计学意义（P〉0.05）。结论恒速静脉输注异丙酚51 min时,颈内动脉和静脉血药浓度达平衡状态;异丙酚在犬脑各区域分布均衡;伤害性刺激时背侧丘脑和底丘脑异丙酚浓度较高,而在犬脑其他各解剖区域呈均衡分布。

Objective To observe the distributional characteristics of propofol in different anatomic region of the dogs brain under the conditions of noxious stimuli with the equilibrium of blood drug level between internal carotid artery and internal jugular vein. Methods Twelve healthy hybrid dogs of male or female, aged 12 - 18 months and weighed 10 - 12 kg,were divided randomly into stimulation group and control group （n = 6）. All dogs were given propofol 7 mg · kg^-1 by intravenous injection at a single dose, and then was maintained with propofol continously infused at a constant rate of 70 mg·kg^-1·h^-1. In stimulation group, the tails of the dogs were clamped for 1 min after 50 min of propofol infusion,while incontrol group, nothing was done to the dogs. The blood samples 2 mL were taken from the internal carotid artery and the internal jugular vein respectively for measurement of propofol concentrations in the plasma at the 50th min （ control group） and 51th min （ stimulation group） after the start of the infusion. Then the dogs were sacrificed by decapitation. The thalamus, epithalamus, metathalamus, hypothalamus, subthalamus, frontal lobe, parietal lobe, temporal lobe, hippocampus, cingulate gyrus, cerebellum, midbrain, pons, medulla oblongata and cervical cord were taken for the determination of propofol concentrations in plasma and brain tissues by high-pressure liquid chromatography （HPLC）. Results The plasma concentrations of propofol in internal carotid artery and internal jugular vein were （6.16 ± 1.04） ug·g^-1 and （6.16 ± 0.49）ug·g^-1, which there were no statistical differences （P 〉 0.05）. The propofol concentrations in the thalamus and subthalamus were significantly higher than those of any other brain tissues （P 〈 0. 05） ; and there were no statistical differences of propofol concentrations among other brain tissues （P 〉 0.05 ）. The propofol concentrations in internal carotid artery and internal jugular vein were （6.17 ± 1.00）ug·g^-1 and （6.16±0.96）ug·g^-1,there were no statistical differences （P 〉 0.05）. Conclusion The plasma propofol concentrations of internal carotid artery and internal jugular vein reached equilibrium at the 51th min of propofol constant infusion, and propofol achieve a balanced distribution in all encephalic region. The concentration of propofol in dorsal thalamus and subthalamus were higher than that in other encephalic region ;There was a equilibrious distribution of propofol in other anatomic region of the brain.