日本血吸虫胆碱酯酶的组织化学定位

血吸虫的胆碱酯酶(ChE)与血吸虫神经介质的传递、肌肉活动以及与其它物质代谢均有密切关系,也是抗血吸虫药物作用的靶子之一。1959年沈美玲等进行了药物对日本血吸虫乙酰胆碱酯酶(AChE)活力的研究。最近,姚民一等(1981)采用等电聚焦电泳分离出日本血吸虫胆碱酯酶的同功酶。然而有关血吸虫胆碱酯酶的组织化学定位研究主要限于曼氏血吸虫(Pepler,1958;Lewert等,1965;Fripp,1967;Bueding等,1967;Bruckner等,1974;Diconza等,1975)除Bueding简单述及日本血吸虫成虫的AChE外,迄今国内外尚无日本血吸虫CbE的组化资料,而且日本血吸虫的神经系统也未被专门观察。由于ChE的组化定位能细致地显示出血吸虫的神经系统构造,并能进一步提

HISTOCHEMICAL LOCALIZATION OF CHOLINESTERASE IN VARIOUS STAGES OF SCHISTOSOMA JAPONICUM

The nervous system of various stages of Schistosoma japonicum was demonstrated by Koelle-Gomori's method, as modified by Douglas for localization of acetylcholines-terase (AChE). By using this method, A ChE activity was found in the ganglia, longitudinal nerve trunks, transverse nerve commissures and finer nerve fibres of 8. japonicum. A small amount of nonspecific cholinesterase was also found to occur together with the specific AChE.The nervous system of the miracidium is composed of a thick neural mass, three pairs of longitudinal nerve trunks and a pair of transverse arched nerve trunks at the anterior half of the body; and three pairs of longitudinal nerve trunks arising from the neural mass and merging posteriorly into a pair of lateral trunks at the posterior third of the body.In cercaria, there are two compact nerve ganglia connected by a thick nerve com- missure and three pairs of longitudinal nerve trunks, namely dorsal, lateral and ventral ones, which extend to the anterior and posterior regions bilaterally and symmetrically. The ventral nerve trunks are the most conspicuous of the three and supply nerve ring in the acetabulum. In the tail there are two, pairs of longitudinal nerve trunks which are prolongations of the branches of dorsal nerve trunks from the body. The AChE positive papillar sensory organs are found on the surface of the organism, and their patterns resemble those of Sakamoto's argentophilic papillae.The nervous system of a 2-day-old sehistosomulum shows the same pattern as that of cercarial body, but in some of them the papillae on the tegument have disappeared. During the development of schistosomula, the central nerve ganglia enlarge and the nerve trunks elongate. In 10-day-old sehistosomulum, a perfect nervous system is seen and its longitudinal nerve trunks extend to the oral sucker, and the nerve ring in the acetabulum is conspicuous. A lot of transverse nerve connectives innervating the gyneeophoral canal can be observed in the male specimens of 17 days old. From then on, the nervous system of the juveniles is very similar to that of adults.In adults, the central nervous system is revealed as two nerve ganglia which are connected by a thick dorsal nerve commissure in the middle region of the oesophagus. Three pairs of longitudinal nerve trunks, ventral, dorsal and lateral, arise from the ganglia, run to the anterior and posterior parts of the body, and join at the posterior end following the contour of the body. The ventral pair is the best developed and its branches lead into the acetabulum forming a nerve ring, while the three nerve trunks extend anteriorly into the oral sucker and ramify around its lips to form a network.As indicated by our experiments on intact adults, the final concentrations of compounds inhibiting the AChE activity of the acetabulum and the oral sucker were lower than those of the longitudinal nerve trunks and the eentral ganglia. The cholinesterase of S. japonicum was more sensitive to the inhibitory effects of eserine than to metri-fonate, BW284C51 and 62C47. The effect of iso-OMPA on cholinesterase as evidenced by histochemieal method was also given.Finally, the histochemistry of cholinesterase between S. japonicum and S. mansoni was briefly discussed and compared.