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PubMed1989

In vitro inhibition of methionine incorporation in the dorsal bodies of Helix aspersa by synthetic FMRFamide.

1. In in vitro conditions, synthetic FMRFamide was shown to inhibit the uptake of labelled methionine by the dorsal bodies (DB)-containing connective tissue of Helix aspersa. 2. This effect occurred at physiological concentrations and in a dose-dependent manner. 3. Among the different cell types of the explants, the DB cells preferentially incorporated the radioactive precursor. 4. These results suggest that FMRFamide plays a biological role in controlling the DB activity (protein synthesis) of Helix aspersa.

Animals↗
PubMed1991

FMRFamide-like immunoreactivity in the ventral ganglion of the fly Sarcophaga bullata: metamorphic changes.

1. Localization of FMRFamide-like immunoreactivity was examined in the ventral ganglion of the fly Sarcophaga bullata using the indirect immunofluorescent method. 2. There are six large cells in the thoracic ganglion which are highly immunoreactive at all stages of development. 3. During metamorphosis the thoracic FLI neurons shift their position from ventrolateral to mid-ventral position and their axons terminate and elaborate a highly immunoreactive dorsal neural sheath. 4. It is suggested that the dorsal neural sheath may function as a neurohaemal organ from which FMRFamide-like substances may be released into the haemolymph to act as neurohormones.

Amino Acid Sequence↗
PubMed2004

The influence of diet and feeding state on FMRFamide-related peptides in the gut of Locusta migratoria L.

Gut tissues of 2-week post-ecdysis female Locusta migratoria L. were assayed for FMRFamide-like immunoreactivity (FLI) during various feeding states using both radioimmunoassay and immunohistochemistry. The feeding states investigated were: (a) 48- and 24-h starved; (b) 5-, 30-, or 60-min post-feeding initiation; and (c) a diet of wheat grass, carrots, or apples. We determined: (1) the feeding state of a locust influences FLI in all gut tissues; (2) variations in diet appear to influence FLI in all gut tissues; (3) more than one FMRFamide-related peptide (FaRP) responds to differences in diet and state of starvation in the gut tissues; and (4) the protein poor diets (carrot and apple), in conjunction with the assertion that protein to carbohydrate ratio in the diet is the key component for nutrient balancing, suggests that FaRPs may play a role in maintaining balanced nutrient content in the locust.

Animals↗
PubMed2006

Rat NPFF(1) receptor-mediated signaling: functional comparison of neuropeptide FF (NPFF), FMRFamide and PFR(Tic)amide.

Neuropeptide FF (NPFF) participates in many physiological functions associated with opioids in the mammalian CNS. We established a pheochromocytoma PC-12 cell line clone stably expressing rat NPFF1 receptors. Both NPFF and FMRFamide activated NPFF1 receptors to couple with Gi/o protein and inhibited adenylyl cyclase activity in PC-12/rNPFF1 cells, but there were no effects on MAPKs (ERK1/2 and p38 MAPK) or PI3K/Akt pathway. FMRFamide also inhibited DARPP-32/Thr34 phosphorylation in the presence of forskolin. Similarly, PFR(Tic)amide, a 'super-agonist' of NPFF receptors, inhibited the production of cAMP and slightly decreased DARPP-32/Thr34 phosphorylation in PC-12/rNPFF1 cells. Intracerebroventricular injections of PFR(Tic)amide blocked behavioral sensitization of locomotor activity to amphetamine, and intrathecal injection of PFR(Tic)amide caused a dose-dependent antinociception in vivo in rats. Thus, "over-activation" of NPFF receptors by PFR(Tic)amide induced different bio-effects from those induced by NPFF in vivo.

Adenylyl Cyclases↗
PubMed2006

The spatial relationship between the musculature and the NADPH-diaphorase activity, 5-HT and FMRFamide immunoreactivities in redia, cercaria and adult Echinoparyphium aconiatum (Digenea).

The spatial relationship between the musculature and the NADPH-diaphorase (NADPH-d) activity, 5-HT and FMRFamide immunoreactivities in redia, cercaria and adult Echinoparyphium aconiatum was studied using scanning electron microscopy (SEM), NADPH-d histochemistry, immunocytochemistry, and confocal scanning laser microscopy (CSLM). TRITC-conjugated phalloidin was used to stain the musculature. Staining for NADPH-d was observed in the central (CNS) and peripheral nervous system (PNS) of all three stages. NADPH-d positive nerves occurred very close to muscle fibres. 5-HT-immunoreactive (5-HT-IR) nerve cells and fibres occurred in the CNS and PNS and close to muscle fibres. FMRFamide-IR nerve fibres were observed in the CNS and PNS of adult worms. This is the first time, the presence of the NADPH-d has been demonstrated in the larval as well as the adult stages of a fluke.

Animals↗
PubMed1997

GABA-immunoreactive neurones and interactions of GABA with serotonin and FMRFamide in a peripheral sensory ganglion of the pond snail Lymnaea stagnalis.

The osphradium is a putative chemosensory organ of aquatic molluscs. Previously, we identified cells with serotonin (5-HT) and FMRFamide (FMRFa)-like immunoreactivity in the osphradial ganglion of Lymnaea stagnalis. The present investigation has established the presence of cells immunoreactive to gamma-aminobutyric acid (GABA). Some of these cells send processes to the sensory epithelium and are thus considered to be primary sensory neurones. Colocalisation of GABA and FMRFamide-like immunoreactivities was found in some of these and other neurones. The responses of the osphradial output electrical activity to the single and combined application of the above neuroactive substances were examined. 5-HT slightly increased and FMRFa decreased the activity. GABA alone was generally ineffective; however, it had a consistent stimulating effect after pretreatment with 5-HT. In its turn, pretreatment with GABA significantly increased the inhibitory action of FMRFa. Primary sensory neurones giving this kind of responses in the nerve were identified electrophysiologically and morphologically in the osphradial ganglion. Our results indicate that GABA takes part in relay of sensory signals into the central nervous system, and transmitter interactions involving GABA, 5-HT, and FMRFa are considerable for the final output pattern of the osphradial sensory network.

Animals↗
PubMed1999

FMRFamide-related neuropeptide gene family in Caenorhabditis elegans.

Neuropeptides are used as signaling molecules in the nervous system of most organisms, including mammals. The family of FMRFamide (Phe-Met-Arg-Phe-NH2)-like neuropeptides (FaRPs) all share an RFamide sequence at their C-termini and have been shown to have diverse functions in the central and peripheral nervous systems. In the nematode Caenorhabditis elegans, FMRFamide-like peptides (FaRPs) are expressed in at least 10% of the neurons, including motor, sensory, and interneurons that are involved in movement, feeding, defecation, and reproduction. Twenty-two genes, designated flp-1 through flp-22, encode FaRPs in C. elegans, although there are likely to be additional flp genes to be identified. Each flp gene encodes a different set of FaRPs, yielding a predicted total of 59 distinct FaRPs; a few of the genes may also encode non-FaRPs. Inactivation of some of the flp genes indicates that at least one flp gene has unique functions, while at least two flp genes appear to have overlapping functions with other flp genes. These results suggest that a complex family of FaRPs have varied roles through all stages of development and in adulthood in C. elegans.

Animals↗
PubMed1997

A human gene encoding morphine modulating peptides related to NPFF and FMRFamide.

FMRFamide-related peptides have been isolated from both invertebrates and vertebrates and exhibit a wide range of biological effects in rats. We show here that in humans 2 FMRFamide-related peptides are encoded by a single gene expressed as a spliced mRNA. The larger predicted peptide (AGEGLNSQFWSLAAPQRFamide) differs from the peptide isolated from bovines (AGEGLSSPFWSLAAPQRFamide) by the substitutions of 2 amino acids. The shorter predicted peptide (NPSF, SQAFLFQPQRFamide) is 3 amino acids longer than the bovine 8 amino-acid NPFF (FLFQPQRFamide) or the human NPFF peptide isolated from serum [5], suggesting that the encoded protein is subject to cleavage by a tripeptidyl peptidase or by a novel processing mechanism. On rat spinal cord, the larger peptide is indistinguishable in activity from the equivalent bovine peptide whereas the smaller extended peptide is inactive.

Action Potentials↗
PubMed2002

Localisation of Globodera pallida FMRFamide-related peptide encoding genes using in situ hybridisation.

The present study employed an in situ hybridisation technique to detect the expression of a number of FMRFamide-like peptide encoding (flp) genes, previously identified from Globodera pallida, in whole-mount preparations of the J(2) stage of this worm. gpflp-1, encoding the FMRFamide-related peptide (FaRP) KSAYMRFamide, was expressed in neurones associated with the circumpharyngeal nerve ring and specifically in a number of cell bodies in the lumbar ganglia of the perianal nerve ring. The lumbar ganglia and pre-anal ganglia along with the BDU neurones and a number of cells in the retrovesicular ganglion were observed to express gpflp-2, encoding KNKFEFIRFamide. gpflp-3 (encoding KHEYLRFamide) expression was localised to the anterior ganglion and a number of paired cells posterior to the circumpharyngeal nerve ring whilst expression of gpflp-4, encoding a number of -P(G/Q)VLRFamides, was localised to the retrovesicular ganglion. No expression of gpflp-5 was observed. Identification of the reactive cells has implicated distinct roles for the FaRPs encoded on these genes in regulation of both dorsal and ventral body wall muscles, the musculature of the vulva and in the function of a number of sensory structures in both the head and tail of G. pallida. Comparison with the expression patterns of analogous genes in Caenorhabditis elegans suggests that, whilst some of the encoded peptides are conserved between nematode species, their functions therein are distinct. Furthermore, the expression of some of these genes in a number of interneurones supports the idea that FaRPs fulfil neuromodulatory as well as neurotransmitter roles.

Amino Acid Sequence↗
PubMed1985

Aplysia neurons express a gene encoding multiple FMRFamide neuropeptides.

The neuroactive peptide Phe-Met-Arg-Phe-NH2 (FMRF-amide) has a variety of effects on both mammalian and invertebrate tissues; moreover, FMRFamide-like immunoreactivity is found throughout the animal kingdom. Here we describe the isolation and characterization of a cDNA clone from an Aplysia abdominal ganglion cDNA library that encodes a precursor protein that may give rise to as many as 19 individual FMRFamide peptides. Nearly all of the FMRF sequences are flanked on the amino terminus by Lys-Arg residues and on the carboxy terminus by Gly-Lys residues, suggesting that the single lysine residues function to signal cleavage by processing enzymes. The gene is present in a single copy per haploid genome and gives rise to multiple transcripts, at least some of which appear to arise through alternate RNA splicing. Immunohistochemical analysis suggests that the peptide is present in many neurons throughout the Aplysia nervous system and that these neurons send processes to a variety of different tissues.

Amino Acid Sequence↗
PubMed1998

FMRFamide-related gene family in the nematode, Caenorhabditis elegans.

Many organisms, including mammals, use short peptides as neurotransmitters. The family of FMRFamide (Phe-Met-Arg-Phe-NH2)-like neuropeptides, which all share an -RFamide sequence at their C-termini, has been shown to have diverse functions, including neuromodulation and stimulation or inhibition of muscle contraction. In the nematode, Caenorhabditis elegans, FMRFamide-like peptides (FaRPs) are expressed in approximately 10% of the neurons, including motor, sensory, and interneurons that are involved in movement, feeding, defecation, and reproduction. At least 14 genes, designated flp-1 through flp-14, encode FaRPs in C. elegans. Here, we present data that all 14 flp genes are transcribed in C. elegans, and several of these genes are alternatively spliced. Each flp gene encodes a different set of FaRPs, yielding a predicted total of 44 distinct FaRPs. Using staged RNA for reverse-transcription/polymerase chain reactions (RT/PCR), we determined that most flp genes are expressed throughout development. These results suggest that a complex family of FaRPs have varied roles through all stages of development and in adulthood in C. elegans.

Amino Acid Sequence↗
PubMed1996

Receptor inactivation by dye-neuropeptide conjugates. 3. Comparative binding of dye-neuropeptide conjugates to FMRFamide receptors of Helix aspersa and Loligo pealei.

Three neuropeptide analogues of FMRFamide (FMRFa) were covalently attached to a tethered derivative of methylene blue to form dye-neuropeptide conjugates. The comparative binding of the latter to FMRFa receptors was subsequently examined in both Helix aspersa (circumesophageal ganglia) and squid (optic lobe membrane). In Helix, the FMRFa analogue CFMRFamide (CFMRFa) inhibited the specific binding of the FMRFa ligand [125I]daYFnLRFa in a dose-dependent manner. Az-CFMRFa, one of the dye-neuropeptide conjugates, also dose-dependently inhibited the specific binding of [125I]daYFnLRFa. Moreover, their potencies equaled or exceeded that of FMRFamide. In squid, the binding of CFMRFa and FMRFa was similar. However, the dye-neuropeptide conjugate (IC50 of 14 nM) was about 44-fold less potent than FMRFa. The conjugates were synthesized as part of a study seeking to target and inactivate preselected receptors with heretofore unattainable selectivity and permanence.

Animals↗
PubMed1992

FMRFamide-like immunoreactivity in the brain and pituitary of the goldfish, Carassius auratus.

The distribution of FMRFamide-like immunoreactivity was determined in the brain and the pituitary of the goldfish, Carassius auratus. Immunoreactive perikarya were observed in the olfactory nerve, nucleus entopeduncularis, nucleus anterioris periventricularis, nucleus posterioris periventricularis, lateral part of the nucleus lateralis tuberis pars posterioris, midbrain tegmentum, and medulla oblongata. Immunoreactive fibers were widely distributed in the brain, in particular in the ventral telencephalon and the hypothalamus. A few immunoreactive nerve fibers were observed in the pituitary. The findings are discussed in relation to male sexual behavior and the involvement of FMRFamide-like peptide in pituitary functions in the goldfish.

Animals↗
PubMed2002

Seven novel FMRFamide-like neuropeptide sequences from the eyestalk of the giant tiger prawn Penaeus monodon.

FMRFamide-like immunoreactivity (FLI) was localized in the eyestalk of Penaeus monodon by immunohistochemistry using a combination of three anti-FMRFamide-like peptide (FLPs) monoclonal antibodies. Approximately 3000 small neuronal cell bodies in the lamina ganglionalis; 100 medium to large size at the ganglion between the medulla interna and the medulla terminalis; and 250 medium size around the medulla terminalis were stained intensely. The neuronal processes in neuropils of the medulla externa, medulla interna, medulla terminalis, sinus gland and some nerve fibers in the optic nerve were also recognized. The small cell bodies, approximately 1500 cells, anterior to the medulla externa were stained inconsistently and the neuronal processes were not observed from these cells. Isolation of FLPs from 9000 eyestalks was performed using methanol/acetic/water (90:1:9) extraction. After the extract was partially purified using C18 cartridges, it was further purified by five to seven steps of RP-HPLC using three kinds of columns: C18; C8; and cyano, and three solvent systems: acetonitrile/trifluoro acetic acid; aceonitrile/heptafluoro butyric acid; and acetonitrile/triethyl ammonium acetate. Dot-ELISA using the combination of the same antibodies was used to monitor FLPs in the fractions during purification processes. Seven new sequences of FLPs were identified which can be divided into four subgroups according to the primary structure of the C-terminus: (1) GDRNFLRFamide; (2) AYSNLNYLRFamide; (3) AQPSMRLRFamide, SQPSMRLRFamide, SMPSLRLRFamide and DGRTPALRLRFamide; and (4) GYRKPPFNGSIFamide. These data indicate the high complexity of this peptide family in which multiple forms are usually exist.

Amino Acid Sequence↗
PubMedDate not supplied

Neuronal inhibition by the peptide FMRFamide involves opening of S K+ channels.

Neurotransmitters modulate the activity of ion channels through a variety of second messengers, including cyclic AMP, cyclic GMP and the products of phosphatidylinositol breakdown. Little is known about how different transmitters acting through different second-messenger systems interact within a cell to regulate single ion channels. We here describe the reciprocal actions of serotonin and the molluscan neuropeptide, FMRFamide, on individual K+ channels in Aplysia sensory neurons. In these cells, serotonin causes prolonged all-or-none closure of a class of background conductance K+ channels (the S channels) through cAMP-dependent protein phosphorylation. Using single-channel recording, we have found that FMRFamide produces two actions on the S channels; it increases the probability of opening of the S channels via a cAMP-independent second-messenger system and it reverses the closures of S channels produced by serotonin or cAMP.

Animals↗
PubMed1989

FMRFamide reverses protein phosphorylation produced by 5-HT and cAMP in Aplysia sensory neurons.

Neurotransmitter can modulate neuronal activity through a variety of second messengers that act on ion channels and other substrate proteins. The most commonly described effector mechanism for second messengers in neurons depends on protein phosphorylation mediated by one of three sets of kinases: the cyclic AMP-dependent protein kinases, the Ca2+-calmodulin-dependent protein kinases, and the Ca2+-phospholipid-dependent protein kinases. In addition, some neurotransmitters and second messengers can also inhibit protein phosphorylation by lowering cAMP levels (either by inhibiting adenylyl cyclase or activating phosphodiesterases). This raises the question: can neurotransmitters also modulate neuronal activity by decreasing protein phosphorylation that is independent of cAMP? Various biochemical experiments show that a decrease in protein phosphorylation can arise through activation of a phosphatase or inhibition of kinases. In none of these cases, however, is the physiological role for the decrease in protein phosphorylation known. Here we report that in Aplysia sensory neurons, the presynaptic inhibitory transmitter FMRFamide decreases the resting levels of protein phosphorylation without altering the level of cAMP. Furthermore, FMRFamide overrides the cAMP-mediated enhancement of transmitter release produced by 5-hydroxytryptamine (5-HT), and concomitantly reverses the cAMP-dependent increase in protein phosphorylation produced by 5-HT. These findings indicate that a receptor-mediated decrease in protein phosphorylation may play an important part in the modulation of neurotransmitter release.

Animals↗
PubMed1996

Isolation, localization, and bioactivity of the FMRFamide-related neuropeptides GYIRFamide and YIRFamide from the marine turbellarian Bdelloura candida.

Two FMRFamide-related neuropeptides, GYIRFamide and YIRFamide, were isolated from the marine turbellarian Bdelloura candida. The peptides elicited a dose-dependent contraction of isolated turbellarian muscle fibers, and both were more potent than FMRFamide. Structure-activity studies, using a range of analogues of the tetrapeptide amide, indicated that the structure of the endogenous peptides was optimal for peak activity. Immunocytochemistry, using an autologous antiserum, revealed a widespread distribution of peptide immunoreactivity within central and peripheral neurons and their processes. This study indicates an important role for GYIRFamide and YIRFamide in the control of neuromuscular function in turbellarians.

Amino Acid Sequence↗
PubMed2000

The brain of the Nemertodermatida (Platyhelminthes) as revealed by anti-5HT and anti-FMRFamide immunostainings.

The taxa Nemertodermatida and Acoela have traditionally been considered closely related and classified as sister groups within the Acoelomorpha Ehlers 1984 (Platyhelminthes). Recent molecular investigations have questioned their respective position. In this study, the 5-HT and FMRFamide immunoreactivity (IR) in the nervous system of two nemertodermatids, Nemertoderma westbladi and Meara stichopi, is described. The 5-HT immunoreactive pattern differs in the two nemertodermatids studied. In M. stichopi, two loose longitudinal bundles of 5-HT-immunoreactive fibres and an basi-epidermal nerve net were observed. In N. westbladi the 5-HT-IR shows a ring-shaped commissural structure, different from the commissural brain of acoels. In both nemertodermatids, FMRFamide immunoreactive nerve fibres followed the 5-HT-immunoreactive fibres. It is demonstrated that the Nemertodermatida have neither a 'commissural brain' structure similar to that of the Acoela, nor a 'true', ganglionic brain and orthogon, typical for other Platyhelminthes. The question of the plesiomorphic or apomorphic nature of the nervous system in Nemertodermatida cannot yet be answered. The neuroanatomy of the studied worms provides no synapomorphy supporting the taxon Acoelomorpha.

Animals↗