Premium
Immunocytochemical study of the postnatal development of 5‐HT‐containing neurons and fibers in the cerebroid ganglia of Cryptomphalus aspersa
Author(s) -
Flores Vladimir,
Brusco Alicia,
Saavedra Jorge Pecci
Publication year - 1988
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/0736-5748(88)90019-6
Subject(s) - serotonergic , hatching , biology , anatomy , plexus , ganglion , expansive , growth cone , neurite , neuroscience , serotonin , axon , ecology , in vitro , biochemistry , compressive strength , receptor , materials science , composite material
In this work we have studied the organization of the serotonergic system in new‐hatched snails and the developmental changes that occur postnatally. The serotonergic system of the newhatched snail is not completely developed. Tracts previously described in the adult were already present at hatching; however immunoreactivity of these tracts was somewhat less intense than that in adults, but, their location was practically the same. At hatch the pro‐ and postcerebral serotonergic plexi were poorly developed, while the mesocerebral one was nearly absent. The procerebral plexus occupied only the caudal half of the procerebral neuropile. Growth cone profiles were found in all plexi. The paired giant dorsal serotonergic neurons were the only stained neurons constantly found at hatching; they were symmetrically located. The paired medium‐sized neurons were not found in all brains examined. Sometimes only one of them was present at hatching; it was located either in the right or in the left ganglion. The small neurons were absent in most cases. They gradually appeared during the first three postnatal months. Following hatching the procerebral plexus had undergone an intense growth. By the third postnatal month it innervated completely the procerebral neuropile. At hatching the area innervated by the procerebral plexus was 4500 μm 2 , by the third month this area was about 58,000 μm 2 and in the adult was 80,000 μm 2 . The postnatal development of the procerebral serotonergic plexus proceeds through two different modalities of neuritic growth: expansive growth is mediated by centrifugal elongation of terminal branches while the increase in fiber density within the plexus results from lateral sprouting. This growth probably depends on dynamic interactions with afferent fibers proceeding from the tentacular sensory organs.