Methylxanthine inhibition of neurosecretion in the brain and corpus cardiacum of Cecropia

The fine-structure of the median neurosecretory cells and corpora cardiaca of the Cecropia silkmoth during the first 7 days after transfer from cold conditions to room temperature was compared to that of similar animals whose development was arrested with aminophylline. The major difference observed was the failure of the intrinsic secretory cells of the corpus cardiacum to degenerate in the arrested animals. This failure to degenerate coincides with the expected period of brain hormone release. After long periods of arrest, the medial neurosecretory cells and their axons became distended with neurosecretory granules. The significance of these observations in the initiation of adult development is discussed.