Two FMRFamide-like peptides, FMRFamide (Phe-Met-Arg-Phe-NH(,2)) and pQDPFLRFamide (pyroGlu-Asp-Pro-Phe-Leu-Arg-Phe-NH(,2)), were characterized and quantified from twenty three tissues of the snail, Helix aspersa. The peptides were widely but unevenly distributed in Helix, and were most concentrated in the central ganglia, male reproductive tract, posterior digestive system, tentacles and the blood. These peptides were localized in the peripheral tissues with immunocytochemical techniques. In all tissues, the peptides were observed exclusively in perikaria, nerves and nerve varocosities, and the density of staining was well correlated with the concentration measured by radioimmunoassay. Five select tissues, containing different concentrations of the endogenous peptides, were surveyed for their responses to FMRFamide, pQDPFLRFamide, acetylcholine (ACh) and 5-hydroxytryptamine (5-HT). The responses to the peptides were distinguishable from those of ACh and 5-HT, and were diverse: excitatory effects were observed in the epiphallus and ventricle; biphasic effects were seen in the tentacle and pharyngeal retractor muscles; and inhibition occurred in the crop. Moreover, the responses to FMRFamide and pQDPFLRFamide peptide were not always the same. FMRFamide contracted the tentacle and pharyngeal retractor muscles whereas pQDPFLRFamide rarely had effects alone, but relaxed ACh and FMRFamide induced contractions. In Aplysia, FMRFamide was separated from SCP(,B) ("small cardioactive peptide", previously identified in Aplysia) by gel and ion-exchange chromatography, and was sequenced by sequential digestion with carboxypeptidase Y. Furthermore, FMRFamide and SCP(,B) have distinct biological actions, and their distribution amongst the central ganglia are different. / Source: Dissertation Abstracts International, Volume: 46-01, Section: B, page: 0073. / Thesis (Ph.D.)--The Florida State University, 1984.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_75507 |
| Contributors | LEHMAN, HERMAN KENNETH., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 160 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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