title: Amine-containing neurons in the brain of Lymnaea stagnalis: distribution and effects of precursors.
abstract: Glyoxylic acid-induced fluorescence in whole-brain preparations of the central nervous system of the freshwater pond snail, Lymnaea stagnalis, was used to map the distribution of serotonin-and dopamine-containing neurons. Serotonin and dopamine were easily distinguishable by differences in color of fluorescence. Serotonin-containing neurons were consistently found in the cerebral, pedal, right parietal and visceral ganglia. Dopamine-containing neurons were found in the pedal, and buccal ganglia. Prior incubation of brains in 5-hydroxytryptophan (5-HTP), the immediate precursor to serotonin, produced serotonin-like fluoresence in neurons which do not normally fluoresce. These neurons thus probably possess specific uptake mechanisms for 5-HTP. Since 5-HTP itself fluoresces yellow, the glyoxylic acid technique cannot determine if these neurons contain the enzyme aromatic amino acid decarboxylase, which converts 5-HTP to serotonin, or merely fluoresce because of the 5-HTP taken into the cells.
authors.forename: G
authors.initials: G
authors.lastname: Audesirk
mesh_terms: D006916:5-Hydroxytryptophan / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000166:cytology* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D005724:Ganglia / Q000166:cytology / Q000378:metabolism; D006038:Glyoxylates; D008195:Lymnaea; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*
chemical_list: D006038:Glyoxylates; D012701:Serotonin; D006916:5-Hydroxytryptophan; C031150:glyoxylic acid; D004298:Dopamine