摘要
用电生理学方法研究了灭多威对美洲大蠊Periplanetaamericana腹六神经节(A6节)突触传递的影响。用灭多威溶液浸泡A6节,电刺激尾须神经粗支,用甘露醇间隙法记录兴奋性突触后电位(EPSP)和突触后动作电位。给予弱刺激只记录到EPSP时,灭多威作用初期EPSP幅度增加、时程延长,能诱发突触后动作电位,随后EPSP逐渐减小至消失,冲洗可恢复,突触前反应保持不变。增加电刺激强度记录到突触后动作电位时,灭多威可阻断A6节的突触传递,阻断时间是浓度依赖性的,阻断是可逆的,但冲洗30min仍保留一定的后作用。对美洲大蠊雄性成虫腹腔注射灭多威测定致死中量(LD50)为(356±001)μg/g体重。根据灭多威的作用机理对其阻断A6节突触传递的特点以及对虫体的毒杀机制进行了讨论。
The effects of methomyl on the synaptic transmission of the 6th abdominal ganglion of cockroach ( Periplaneta americana ) were studied. The ganglions were partially desheathed and immersed in various concentrations of methomyl solution. By stimulation of the bilateral cercal nerves XI at a rate of 1Hz/sec, evoked excitatory post synaptic potential (EPSP) and post synaptic action potential were recorded with mannitol gap method. With weak stimulation only EPSP could be recorded, and under the action of 100 μmol/L methomyl, an increase in the amplitude and duration of the EPSP was first observed, and then post synaptic action potential could be evoked; however, afterwards the amplitude of EPSP reduced progressively until finally disappeared, but the pre synaptic response remained unchanged. The EPSP could be restored by washing cockroach with saline. With strong stimulation, the post synaptic action potentials, superimposed on EPSP, could be recorded. Under the action of methomyl solutions, the synaptic transmission was blocked. The blocking action of methomyl was reversible by washing, however, it still remained some post effect after 30 min washout. The LD 50 for methomyl to adult male cockroach was (3 56±0 01) μg per gram body weight determined by abdominal injection. Based on the action of methomyl on AChE, the basic characteristics of the blocking process and its killing effect to the insect were discussed.
出处
《昆虫学报》
CAS
CSCD
北大核心
2000年第1期1-6,共6页
Acta Entomologica Sinica
