Lithium salts alter the size and morphology of the Madagascar hissing cockroach's neuroendocrine system.

Lithium salts have been used in psychiatry for decades as normothymics. The full mechanism of action of these drugs is not yet known. The limited work on lithium suggests that it may affect brain structure and size in humans and animals. This study aimed to determine the effect of lithium citrate and carbonate on the neuroendocrine system of Madagascar cockroaches. The animals were fed 10 weeks with the control and test diets (enriched with lithium citrate and carbonate at 0.1 and 0.01%, respectively). After anaesthesia, the insects were decapitated, and the brain and retrocerebral complex were removed. The study showed significant changes in the morphology of the examined elements of the neuroendocrine system of insects consuming lithium in the diet, mainly consisting of the enlargement of the examined structures, with increased doses of lithium and the preparation administered in the form of citrate having a greater effect. The morphotic changes in the endocrine system of the Madagascar cockroach exposed to lithium, as shown in this study, may suggest that a similar phenomenon occurs in humans and animals exposed to lithium from the environment, food, or drugs. Further research on this topic may shed more light on the phenomenon.