On the ultrastructural study of brain neurosecretory cells of Hydrophilus olivaceus Fabr. (Polyphaga - Coleoptera).
Ultrastructural studies of neurosecretory cells were made in Hydrophilus olivaceus. Two groups of neurosecretory cells are localized in the dorsum of brain, where one is the median group comprising of 15 neurosecretory cells each and the other consists of two lateral groups comprising of 4 to 6 neurosecretory cells in each. A dual mode of release of neurosecretory products is seen, where one part is released through the axons of the neurosecretory cells and other part directly through the protocerebral region of brain by diffusion. This direct release is more common at the breeding phases of insect. In direct release, the neurosecretory material is first broken down into still smaller granules which can easily diffuse out through the perikarya of brain. Neurosecretory cells show seasonal periodicity.
D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D001517:Coleoptera / Q000648:ultrastructure*