An immunocytochemical search for potential neurotransmitters in larvae of Phestilla sibogae (Gastropoda, opisthobranchia)

Abstract

1. Cells and axons in the cerebral ganglia and cerebral commissure were shown to contain substances labeling positively with antibodies to small cardioactive peptides (SCP) and FMRFamide. Specific neurons and axons in other parts of the central nervous system (CNS) also contained substances reactive to antibodies against these peptides 2. Positive labeling with antibodies to generative enzymes for L-dopa, norepinephrine and acetylcholine was present in the CNS as punctate spots in the pedal ganglia or cerebral commissure or apical organ. 3. The larval swimming structure, the velum, showed specific labeling with anti-dopamine and anti-choline acetyltransferase in linearly arranged varicosities just below the large ciliated cells of this structure. 4. The occurrence of neurotransmitter-like substances, especially catecholamines, just below the large cells that are shed during metamorphic velar loss, provides new evidence for participation of monoamines in molluscan metamorphosis.