TOXICO-KINETICS OF ACONITE ALKALOID IN VIVO

乌头碱是毒性最大的生物碱之一，但由于血液和尿液等生物材料中的毒素难以定量分析，乌头碱在体内的药代动力学尚不清楚。最近，Mizugaki等人将一种选择性的GC-MS离子监测方法应用于毒素的定量测定。(Eisei Kagaku，34,359-365,1988)。本研究的目的是通过对生物样品中乌头碱的测定，研究乌头碱的毒代动力学。利用选定的离子监测方法，对生物样品中乌头碱进行了近一年的定量测定，取得了满意的结果。以次乌头碱为内标，提高了乌头碱分析的准确性。选用体重30-35g的ICR品系雄性小鼠进行动物实验。乌头碱(Sigma Chemical Co.)在0.1M醋酸盐缓冲液(pH 5.0)中溶解，小鼠腹膜内注射…乌头碱对小鼠的半数致死量为0.308 mg/kg。分别于给药后5、15、30、45、60、120min颈椎脱位处死小鼠(n=3)，心脏采血。乌头碱剂量为0.3 mg/kg时，15min血药浓度最高，为17.2 ng/ml，120min血药浓度对数降至5.63 ng/ml。乌头碱在0.35 mg/kg剂量时血药浓度最高，为32.1 ng/ml，与0.3 mg/kg剂量相同，120min时降至10.7 ng/ml。通过绘制乌头碱血药浓度与给药后时间的关系图，得出两种剂量乌头碱在给药30min后的血药浓度曲线。在剂量为0.3 mg/kg和0.35 mg/kg时，消除半衰期(T&lt；1/2&Gt；S)为96.5min和83.0min。总之，我们发现乌头碱的消除速度与两种剂量的血药浓度成正比。我们以前在小鼠中报道过，在0.4 mg/kg的乌头碱剂量下，联合给予河豚毒素(0.01 mg/kg)，作为乌头碱的钠通道拮抗剂，可以延迟小鼠的死亡时间(Y.OHNO等，Tohoku J.Exp.Med，167,155-158,1992)。然而，在本研究中，河豚毒素(0.01 mg/kg)在0.3 mg/kg和0/35 mg/kg乌头碱剂量下并未延缓死亡时间。因此，在继续的研究中，必须结合不同剂量的两种毒素来考察两种毒素在体内的相互作用。较少

Aconitine is one of the most toxic alkaloids, however, the pharmacokinetics is largely unknown mainly due to the difficulty in quantitative analysis of the toxin from biological materials, such as blood and urine. Recently, a Selected Ion Monitoring Method using GC-MS has been applied to the quantitative determination of the toxin by Mizugaki et al. (Eisei Kagaku, 34,359-365,1988). The purpose of this study is to investigate the toxico-kinetics of aconitine by measuring it in the biological specimens. By using the Selected Ion Monitoring Method, we have gotten the satisfactory results of quantitative determination of aconitine from the biological specimens, though we costed almost a year. Moreover, we improved the more accurate analysis of aconitine by using hypaconitine as the internal standard.Male mice of ICR strain weighing 30-35 g were used for animal experiments. Aconitine (Sigma Chemical Co.) was dissolved in a 0.1 M acetate buffer (pH 5.0), and mice were injected intraperitenea … More lly with the toxin at the doses of 0.3 or 0.35 mg/kg (LD_<50> of aconitine for mice is known to be 0.308mg/kg i.p.). The mice were killed by cervical dislocation at 5,15,30,45,60, and 120 min after the administration (n=3, respectively), and blood samples were collected from the heart. At a dose of 0.3 mg/kg of aconitine, the blood concentration reached to the maximum, 17.2 ng/ml, at 15min, and decreased logarithmically to 5.63 ng/ml at 120 min. At a dose of 0.35 mg/kg of aconitine, the blood concentration reached to the maximum, 32.1 ng/ml, at the same time as the 0.3 mg/kg dose, and decreased to 10.7 ng/ml at 120 min. By plotting the blood concentrations of aconitine in logaritmic scale against the time after administration, the linear curves of the blood aconitine elimination were obtained after 30 min at both doses. From the curves the elimination velocity constants (K_<el>s) were calculated to be 0.00718 /min and 0.00835 /min, and the elimination half-time (T_<1/2>s) were to be 96.5 min and 83.0 min at doses of 0.3 mg/kg and 0.35 mg/kg, respectively. In conclusion, we revealed that the elimination velocity of aconitine is proportional to the blood concentration at the both doses.We previously reported in mice that the time of death at a dose of 0.4 mg/kg of aconitine was delayd by coadministration of tetrodotoxin (0.01 mg/kg), as antagonist of aconitine in the sodium channel in the exitable membranes (Y.OHNO et al., Tohoku J.Exp.Med., 167,155-158,1992). In this study, however, coadministration of tetrodotoxin (0.01 mg/kg) did not delay the time of death at doses of 0.3 mg/kg and 0/35 mg/kg of aconitine. So, on the continueous studies, the interactions of the two toxins in vivo have to be examined with combinations of various doses of the two toxins. Less