Localization of Peptide Hormone/Neuropeptide-Producing Cells in Insects

Peptide hormone/neuropeptide (PH/NP)-producing cells are widely distributed throughout the central and peripheral nervous systems. Technological progress in immunohistochemistry and in situ hybridization has significantly contributed to our understanding of PH/NP-producing cells. Advanced techniques such as double-label immunochemistry, in situ hybridization, and the use of reporter proteins such as green fluorescent protein have contributed to the construction of PH/NP atlases in several insects. The atlas can provide comprehensive views of neuropeptide distribution and signaling networks. Most neuropeptide genes are expressed in the central and peripheral nervous systems. Specific neuropeptides are produced in the corpora cardiaca, subesophageal ganglion, frontal ganglion, thoracic ganglia, and abdominal ganglia and regulate development and behavior. Peripheral cells are also a source of neuropeptides. In non-nervous organs, enteroendocrine cells in the midgut release multiple neuropeptides to regulate feeding activity and respond to physiological changes in the intestine. These distributed control systems may be beneficial for quick and flexible responses of insects to environmental changes and may contribute to insect survival and prosperity.