FMRFamide
Encyclopedia
FMRFamide 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 it is thought to play an important role in cardiac activity regulation. 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 (Higgins et al., 1978).
FMRFamide is an important neuropeptide in several phyla such as Insecta, Nematoda, Mollusca
and Annelida.
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 .
In invertebrates, the FMFRamide-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 .
Neuropeptide
Neuropeptides are small protein-like molecules used by neurons to communicate with each other. They are neuronal signaling molecules, influence the activity of the brain in specific ways and are thus involved in particular brain functions, like analgesia, reward, food intake, learning and...
from a broad family of FMRFamide-related peptides (FaRPs) all sharing an -RFamide sequence at their C-terminus. First identified in Hard clam
Hard clam
The hard clam , also known as a quahog , round clam, or hard-shell clam, is an edible marine bivalve mollusk which is native to the eastern shores of North America, from Prince Edward Island to the Yucatán Peninsula...
Mercenaria mercenaria it is thought to play an important role in cardiac activity regulation. 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
Cyclic adenosine monophosphate
Cyclic adenosine monophosphate is a second messenger important in many biological processes...
in the ventricular region (Higgins et al., 1978).
FMRFamide is an important neuropeptide in several phyla such as Insecta, Nematoda, Mollusca
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
and Annelida.
It is the most abundant neuropeptide in endocrine cells of insect alimentary tracts along with allatostatin
Allatostatin
Allatostatins are neuropeptide hormones in insects and crustacea. They have a twofold function: they both inhibit the generation of juvenile hormone and reduce their food intake. They are therefore putative targets for insecticide research....
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
Caenorhabditis elegans
Caenorhabditis elegans is a free-living, transparent nematode , about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model...
. 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 .
In invertebrates, the FMFRamide-related peptides are known to affect heart rate
Heart rate
Heart rate is the number of heartbeats per unit of time, typically expressed as beats per minute . Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep....
, blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
, gut motility, feeding behaviour and reproduction. In vertebrates such as mice, they are known to affect opioid
Opioid
An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...
receptors resulting in elicitation of naloxone-sensitive antinociception and reduction of morphine
Morphine
Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
-induced antinociception .