title: Sensory input to growth stimulating neuroendocrine cells of Lymnaea stagnalis.
abstract: Several environmental factors influence the growth of the basommatophoran freshwater snail Lymnaea stagnalis. Growth is hormonally controlled by 4 cerebral clusters of ca 50-75 peptidergic, neuroendocrine Light Green Cells (LGC). The present light, transmission, and scanning electron microscopic study shows that the LGC are synaptically contacted by a tentacle sensory system (TSS). The TSS consists of 2 types of primary sensory neurone, viz. ca 150 S1-cells and ca 50-100 S2-cells. A S1-cell has a non-ciliated dendrite and an axon branch that synaptically contacts the soma of a S2-cell. A S2-cell has a branching, ciliated dendrite. Probably, S1- and S2-cells have different sensory modalities and can integrate sensory information by intersensory interaction. The S2-axons run through the tentacular nerves, the cerebral ganglia, and the intercerebral commissure. In each ganglion S2-axons branch and form synaptic contacts on the axons and somata of the LGC and on glial cells that surround the LGC. In an LGC-cluster, 1-3 LGC-somata are particularly strongly innervated. Probably, the TSS is involved in the environmental control of growth in L. stagnalis.
mesh_terms: D000818:Animals; D001369:Axons / Q000648:ultrastructure; D003712:Dendrites / Q000648:ultrastructure; D004702:Endocrine Glands / Q000648:ultrastructure; D008195:Lymnaea / Q000254:growth & development / Q000648:ultrastructure*; D009457:Neuroglia / Q000648:ultrastructure; D009474:Neurons / Q000648:ultrastructure*; D011984:Sensory Receptor Cells / Q000648:ultrastructure*; D013569:Synapses / Q000648:ultrastructure