Identification of midgut gland motoneurons derived from suboesophageal ganglion of the prawn Penaeus japonicus bate.

Abstract

The suboesophageal ganglion of the prawn Penaeus japonicus was composed of five neuropiles, locally distributed nerve cells, and dorsal axon bundles connecting with the superior and inferior nervous systems. The nerve cells held between giant axons were divided into two dorso-median groups at the surface of the posterior neuropiles. Procion yellow was injected antidromically into neurons connected with the midgut gland. The axons injected with the dye were traced to comparatively large cell bodies in the dorso-median groups. These neurons were derived from two different sites, i.e., two paris of the dorso-lateral and a few members of the dorso-median of the ganglion. A part of the ventral wall of anterior midgut gland received both distal ends of the neurons and a cord-like spongy body connected with the anterior of the ganglion. Little has been known on the routes connecting the midgut gland with the ganglion. These results would provide a possible existence of the motor function of the midgut gland.