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FMRF amide.svg
Other names
FMRF amide; H-Phe-Met-Arg-Phe-NH2; L-Phenylalanyl-L-methionyl-L-arginyl-L-phenylalaninamide
3D model (JSmol)
Molar mass 598.77 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

FMRFamide (H-Phe-Met-Arg-Phe-NH2) is a neuropeptide from a broad family of FMRFamide-related peptides (FaRPs) all sharing an -RFamide sequence at their C-terminus. First identified in Hard clam (Mercenaria mercenaria),[1] it is thought to play an important role in cardiac activity regulation.[2] Several FMRFamied related peptides are known, regulating various cellular functions and possessing pharmacological actions, such as anti-opiate effects.[3] In Mercenaria mercenaria, FMRFamide has been isolated and demonstrated to increase both the force and frequency of the heartbeat through a biochemical pathway that is thought to involve the increase of cytoplasmic cAMP in the ventricular region.[4]

FMRFamide is an important neuropeptide in several phyla such as Insecta, Nematoda, Mollusca, and Annelida.[5] It is the most abundant neuropeptide in endocrine cells of insect alimentary tracts along with allatostatin and tachykinin families, however the neuropeptide’s function is not known. Generally, the neuropeptide is encoded by several genes such as flp-1 through flp-22 in C. elegans. The common precursor of the FaRPs is modified to yield many different neuropeptides all having the same FMRFamide sequence. Moreover, these peptides are not functionally redundant.[6]

In invertebrates, the FMRFamide-related peptides are known to affect heart rate, blood pressure, gut motility, feeding behaviour and reproduction. In vertebrates such as mice, they are known to affect opioid receptors resulting in elicitation of naloxone-sensitive antinociception and reduction of morphine-induced antinociception.[7]

Detection of this neuropeptide is important because its expression lays down the foundation of the CNS in the early stages of development in invertebrates. In recent years, neuromodulatory actions of FMRFamide in invertebrates have become more apparent. This is, in part, due to the extensive studies done on the Planorbid and Lymnaeid families of pond snails.[8]

See also[edit]


  1. ^ Price, D.; Greenberg, M. (1977). "Structure of a molluscan cardioexcitatory neuropeptide". Science. 197 (4304): 670–671. Bibcode:1977Sci...197..670P. doi:10.1126/science.877582. ISSN 0036-8075. PMID 877582.
  2. ^ López-Vera, Estuardo; Aguilar, Manuel B.; Heimer de la Cotera, Edgar P. (2008). "FMRFamide and related peptides in the phylum mollusca". Peptides. 29 (2): 310–317. doi:10.1016/j.peptides.2007.09.025. PMID 18241957.
  3. ^ Rőszer, Tamás; Bánfalvi, Gáspár (2012). "FMRFamide-related peptides: Anti-opiate transmitters acting in apoptosis". Peptides. 34 (1): 177–185. doi:10.1016/j.peptides.2011.04.011. PMID 21524675.
  4. ^ Higgins et al., 1978[full citation needed]
  5. ^ Oetken M, Bachmann J, Schulte-Oehlmann U, Oehlmann J (2004). Evidence for endocrine disruption in invertebrates. Int. Rev. Cytol. International Review of Cytology. 236. pp. 1–44. CiteSeerX doi:10.1016/S0074-7696(04)36001-8. ISBN 9780123646408. PMID 15261735.
  6. ^ Li C, Kim K, Nelson LS (November 1999). "FMRFamide-related neuropeptide gene family in Caenorhabditis elegans". Brain Res. 848 (1–2): 26–34. doi:10.1016/S0006-8993(99)01972-1. PMID 10612695.
  7. ^ Raffa RB, Connelly CD (July 1992). "Supraspinal antinociception produced by [D-Met2]-FMRFamide in mice". Neuropeptides. 22 (3): 195–203. doi:10.1016/0143-4179(92)90162-P. PMID 1331846.
  8. ^ Bulloch AG, Price DA, Murphy AD, Lee TD, Bowes HN (September 1988). "FMRFamide peptides in Helisoma: identification and physiological actions at a peripheral synapse". The Journal of Neuroscience. 8 (9): 3459–69. doi:10.1523/JNEUROSCI.08-09-03459.1988. PMID 3171684.

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