The effect of gamma‐HCH upon the ultrastructure of the neurohaemal organs on the median nerves of the stick insect (Carausius morosus)

Abstract

AbstractTopical application of gamma‐HCH induced considerable ultrastructural changes and damage in the cellular components of the neurohaemal organs on the median nerves of Carausius morosus. The cytoplasm and nucleoplasm of the glial cells became much more opaque to electrons and shrinkage occurred in the cellular wrappings surrounding the nerve axons. The cytoplasm of the tracheal wall cells and end cells also increased in electron density. Damage to the nervous elements was less evident than to the glial cells but some clumping and increase in electron opacity of the axoplasm took place. Neurosecretory granules could fragment and/or become less opaque to electrons. Some axons that lacked a glial‐cell sheath and contained neurosecretory granules appeared to be disrupted or degenerating. At very high doses there was an apparent reduction in the number of storage granules and an increase in exocytotic profiles in some neurosecretory axons. These results are discussed in relation to the possible modes of action of gamma‐HCH upon the nervous system of insects.