The serotoninergic system inCryptomphalus aspersa. Immunocytochemical study with an anti-5-HT antiserum

Publisher Website
Google Scholar
Abstract
This immunocytochemical study of 5‐HT neurons and fibers in the nervous system of C. aspersa corroborate previous findings and describe new 5‐HT neurons and their connections, mainly between the central nervous system and the tentacular sensory organs. We found a number of networks, fascicles, and neurons that show constant and symmetrical location. Three networks were found at the tip of the posterior tentacle: (1) underlying the olfactory epithelium, (2) in the neuropil of the tentacular ganglion (TG), and (3) in the ocular capsule. The TG also contains a ventral 5‐HT fascicle. A group of 30–40 serotoninergic fibers run through the tentacular connective from the postcerebrum to the tentacular ganglion. This 5‐HT fascicle has a lateral position in the postcerebrum (lateral fascicle of the postcerebrum) and a subcortical location in the procerebrum (subcortical fascicle of the procerebrum). The optic nerve also has a small group of 5‐HT fibers. Seven serotoninergic neurons were found in each cerebral ganglion: two giant neurons, one medium‐sized, and four small neurons. Three different types of fascicles are in the postcerebrum: (1) fascicles proceeding from the suboesophageal connectives, (2) a lateral fascicle, and (3) a commisural fascicle. Each cerebral ganglion region (pro‐, meso‐ and postcerebrum) has a 5‐HT network with a particular pattern of distribution and morphology. The suboesophageal ganglia show the highest concentration of 5‐HT neurons (large, medium‐size, and small neurons).