An Immunocytochemical Study of Endocrine Cells in the Gut of a Stomachless Teleost Fish, Grass Carp, Cyprinidae

Nineteen different antisera raised against mammalian hormones were used to identify the occurrence and distribution of endocrine cells in the gut of grass carp (Ctenopharyngodon idellus). Positive reactions were obtained in gut epithelium with antisera gastrin, glucagon, gastric inhibitory peptide, leucine enkephalin, substance P, and bovine pancreatic polypeptide. No immunoreactive product was formed using antisera against somatostatin, 5-hydroxy-tryptamine, insulin, avian pancreatic polypeptide, motilin, cholecystokinin, secretin, neurotensin, vasoactive intestinal polypeptide, bombesin, neuron-specific enolase, prochymosin, and pepsinogen. The exact distribution mapping of six kinds of immunoreactive endocrine cells throughout the gut of grass carp (C. idellus) is presented. The morphological characteristics of immunoreactive endocrine cells is described. Their distribution characteristics and possible modes of secretion and function are discussed. Finally, the possible relationship between the transplantation of these cells in the gastro-entero-pancreatic endocrine system is discussed.

A Suboesophageal Ganglion Cell Innervates Heart and Retrocerebral Glandular Complex in the Locust

The suboesophageal ganglion of the migratory locust Locusta migratoria contains a pair of large neurosecretory cells located posteriorly, close to the sagittal plane. By means of double labelling, it is shown that the cells are immunoreactive to bovine pancreatic polypeptide. Using a combination of electrophysiological, neuroanatomical and immunocytochemical methods, it is shown that the neurones project into the corpora cardiaca with ascending anterior axons and into the lateral cardiac nerve cords with posterior axons that descend into the thoracic and abdominal nerve cord.