Secretory hyperactivity and mitochondrial changes in neurosecretory cells of an insect

Summary The neurosecretory cells of the corpus cardiacum of the desert locust Schistocerca gregaria secrete their hormonal products by exocytosis. The insecticide lindane is known to cause release of hyperglycaemic and adipokinetic neurohormones. Electron microscopy of lindane-poisoned corpora cardiaca reveals many exocytotic omega figures. Mitochondria are affected either directly by the poison or by the consequences of secretory hyperactivity. They occur in increased number, divide, acquire dense mitochondrial granules larger than in the controls, and sometimes line up along plasma membranes, mitochondria in two neighbouring cells forming pairs in juxtaposition. Between two such mitochondria the plasma membranes form a junction-like structure. It is suggested that these effects reflect an excessive calcium entry caused by lindane.This work was supported by a Wellcome-Carlsberg Travelling Research Fellowship awarded to T.N. and by a Commonwealth Scholarship for Postgraduate Research awarded to M.S.