Aminergic systems in pulmonate gastropod molluscs. III. Microspectrofluorometric characterization of the monoamines in the reproductive system.

Histochemical fluorescence (Falck-Hillarp) and microspectrofluorometric (MSF) methods were used to characterize different types of catecholamine-containing cellular elements located in the reproductive system of fresh-water snails (Bulinus truncatus, Planorbarius corneus) and land snails [Archachatina marginata, Helix (Cryptomphalus) aspersa]. Transverse sections through the genital tract display a common structural pattern of tubular differentiations: (1) an internal epithelium bordering the lumen and containing variable numbers of monoaminergic cells; (2) an enveloping sheath of connective and muscular tissue containing fine nerve fibers in the form of a network that exhibits a variable degree of density. MSF determinations showed that the formaldehyde-induced fluorophores of the intraepithelial aminergic cells belong to the following classes: (1) the DOPA/dopamine group in the duct of the albumen gland of B. truncatus and the carrefour of A. marginata; and (2) the norepinephrine/epinephrine group in the duct of the albumen gland and in the oviduct sac of P. corneus. In the reproductive systems of B. truncatus and P. corneus (duct of the albumen gland, oviduct sac, vagina), A. marginata and H. aspersa (duct of the fertilization pocket, origin of the receptaculum seminis, carrefour), the MSF analysis revealed norepinephrine/epinephrine-containing intramural nerve fibers. On the other hand, the small neurons in the vagina of B. truncatus belong to the DOPA/dopamine group.