Expression of FMRFamide gene encoded peptides by identified neurons in embryos and juveniles of the pulmonate snail Lymnaea stagnalis.
Immunoreactivity to antibodies (ABs) against FMRFamide, CARP, and three FMRFamide gene encoded peptides, i.e., EFLRIamide, the non-FMRFamide peptide "SEEPLY," and the 35-amino-acid "acidic peptide," were investigated in developing embryos and juveniles of Lymnaea stagnalis. Five early transient embryonic neurons revealed immunoreactivity to EFLRIamide. One of the early neurons, the central posterior, also expressed SEEPLY and CARP immunoreactivity. Two neurons in the anlage of the left and right parietal ganglia coexpressed immunoreactivity to EFLRIamide (type 1 transcript) and acidic peptide (type 2 transcript). Within the developing ganglia altogether 30 neurons expressed the type 1 transcript, and three expressed the type 2 transcript. No peripheral cells immunoreactive to SEEPLY or acidic peptide ABs were found, whereas bipolar EFLRIamide- and CARP-immunoreactive cells were abundant in the lip, mantle and foot. After hatching, the number of immunoreactive neurons in ganglia increased up to 223 and the neurons expressing tetrapeptides were dominant (91%). No neurons coexpressing type 1 transcript and type 2 transcript could be detected in juveniles and adults. At this time, an extensive innervation is developed in the periphery, including foot, mantle, buccal mass, salivary glands and alimentary tract, established mainly by EFLRIamide-immunoreactive cells and varicose fibers of extrinsic and intrinsic origin. It is suggested that both sensory and regulatory function can be attributed to the FMRFamide gene encoded tetrapeptides throughout embryonic and juvenile development in Lymnaea, whereas heptapeptides are presumed to play a modulatory role.
D000818:Animals; D001931:Brain Mapping; D004625:Embryo, Nonmammalian / Q000737:chemistry; D019835:FMRFamide / Q000235:genetics* / Q000378:metabolism*; D007150:Immunohistochemistry; D008195:Lymnaea / Q000737:chemistry* / Q000196:embryology / Q000254:growth & development; D009024:Morphogenesis; D009474:Neurons / Q000737:chemistry*; D010455:Peptides / Q000235:genetics* / Q000378:metabolism*
D010455:Peptides; D019835:FMRFamide