Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “FMRFamide”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39Linked to original sources
PubMed2004

Morphology and electrophysiological properties of neurons projecting to the retrocerebral complex in the blow fly, Protophormia terraenovae.

Morphological and electrical properties of neurons with somata in the pars intercerebralis (PI) and pars lateralis (PL) were examined by intracellular recording and staining in the adult blow fly, Protophormia terraenovae. According to the location of somata and fiber distribution, two types of PI neurons (PIa and PIb) and two types of PL neurons (PLa and PLb) were identified. PIb neurons were further divided into two subgroups of PIb1 and PIb2 depending on fiber branching patterns in the retrocerebral complex. PIa neurons projected axons to the contralateral nervi corporis cardiaci, whereas PLa and PLb neurons projected axons to the ipsilateral nervi corporis cardiaci. PIb neurons characteristically showed symmetrical morphology with their somata along the midline. PLb neurons had a large branching area in the subesophageal ganglion. In the retrocerebral complex, PIb2 and PLa neurons sent fibers into the corpus allatum. PIa, PIb1 and PLb neurons projected not to the corpus allatum but to the corpus cardiacum-hypocerebral complex or visceral muscles in their vicinity. PIa, PIb and PLa neurons showed long spike durations (3-10 ms). PLb neurons were immunoreactive with antisera against corazonin, FMRFamide, or beta-pigment-dispersing hormone. This is the first report revealing the morphology of individual neurons with somata residing in PI and PL in the adult fly.

Animals↗
PubMed2005

Neuroanatomical, immunocytochemical, and physiological studies of the pharyngeal retractor muscle and its putative regulatory neurons playing a role in withdrawal and feeding in the snail, Helix pomatia.

We describe the neurons regulating two separate functions of the pharyngeal retractor muscle (PRM), namely sustained contraction during body withdrawal and rhythmic phasic contractions during feeding, in the snail, Helix pomatia. The distribution of central neurons innervating the PRM is organized into two main units; one in the buccal-cerebral ganglion complex, the other in the subesophageal ganglion complex. Serotonin- (5-HT-), FMRFamide- (FMRFa-), and tyrosine-hydroxylase-immunostained neurons are present among the PRM neurons that densely innervate the PRM. 5HT both decreases and increases the amplitude of the electrically evoked contraction between concentrations of 0.1 microM and 1 microM. Dopamine (DA) only decreases the amplitude of contraction at a 1-microM threshold concentration. In contrast, FMRFa increases the amplitude of the contraction and slightly elevates the tone of the PRM but requires a higher threshold (10 microM). Assay by high-performance liquid chromatography of 5HT and DA in the PRM has shown that the 5HT level decreases during locomotion but increases during feeding, whereas the DA level increases during locomotion but slightly decreases during feeding. Thus, different segments of the PRM are innervated by neurons from different loci within the central nervous system. The segments of the PRM distal to the pharynx are innervated from loci of the subesophageal ganglion complex suggesting that they mediate withdrawal. The proximal segment of the PRM is innervated from cerebral and buccal loci indicating that these neurons mediate the feeding rhythm produced by buccal and cerebral feeding central pattern generators to induce rhythmic phasic contractions in the PRM during feeding.

Animals↗
PubMed2006

Distribution of neuropeptides in the primary olfactory center of the heliothine moth Heliothis virescens.

Neuropeptides are a diverse widespread class of signaling substances in the nervous system. As a basis for the analysis of peptidergic neurotransmission in the insect olfactory system, we have studied the distribution of neuropeptides in the antennal lobe of the moth Heliothis virescens. Immunocytochemical experiments with antisera recognizing A-type allatostatins (AST-As), Manduca sexta allatotropin (Mas-AT), FMRFamide-related peptides (FaRPs), and tachykinin-related peptides (TKRPs) have shown that members of all four peptide families are present in local interneurons of the antennal lobe. Whereas antisera against AST-As, Mas-AT, and FaRPs give similar staining patterns characterized by dense meshworks of processes confined to the core of all antennal-lobe glomeruli, TKRPs are present only in neurons with blebby processes distributed throughout each glomerulus. In addition to local neurons, a pair of centrifugal neurons with cell bodies in the lateral subesophageal ganglion, arborizations in the antennal lobe, and projections in the inner antenno-cerebral tracts exhibits tachykinin immunostaining. Double-label immunofluorescence has detected the co-localization of AST-As, Mas-AT, and FaRPs in certain local interneurons, whereas TKRPs occurs in a distinct population. MALDI-TOF mass spectrometry has revealed nearly 50 mass peaks in the antennal lobe. Seven of these masses (four AST-As, two N-terminally extended FLRFamides, and Mas-AT) match known moth neuropeptides. The data thus show that local interneurons of the moth antennal lobe are highly differentiated with respect to their neuropeptide content. The antennal lobe therefore represents an ideal preparation for the future analysis of peptide signaling in insect brain.

Animals↗
PubMed2001

Monoamines and neuropeptides in antennal lobe interneurons of the desert locust, Schistocerca gregana: an immunocytochemical study.

As a first step towards unravelling some of the complexity of the signalling and modulatory mechanisms in the antennal lobe (AL) of the desert locust Schistocerca gregaria, I analysed the immunocytochemical identity of AL interneurons. Antibodies against serotonin, histamine, locustatachykinin, leucokinin and FMRFamide were used to reveal the morphology of interneurons ramifying in the AL. In addition, double-labelling experiments were performed in order to demonstrate colocalisation of GABA and locustatachykinin and to investigate the ramification patterns of immunolabelled interneurons and physiologically characterised olfactory projection neurons (PNs) injected with Lucifer yellow. Immunoreactivity to these antibodies revealed six different types of interneurons with different patterns of ramification within the glomerular neuropil: (1, 2) Centrifugal interneurons displaying serotonin immunoreactivity, which arborised extensively within the AL and extended varicose fibres into the microglomerular core where close associations with dendrites of AL PNs could be distinguished. (3) Histamine-immunoreactive centrifugal interneurons with arborisations in the protocerebrum and the dorsal non-glomerular regions of the AL and the lobus glomerulatus (LG). (4) Locustatachykinin-immunoreactive local interneurons, colocalising GABA, arborising throughout the AL and extending varicose fibres throughout the glomerular neuropil where close associations with dendrites of AL PNs could be distinguished. (5) Leucokinin-immunoreactive descending neurons connecting the protocerebrum, the AL, the LG and all ganglia of the ventral nerve cord. These neurons displayed sparse innervation of the AL and extended varicose fibres into the interglomerular space. (6) FMRF-amide-immunoreactive centrifugal interneurons, connecting the lateral protocerebrum with the AL and the LG, which arborised sparsely within these neuropils and displayed similar innervation of the microglomeruli as (1) and (2).

Animals↗
PubMed1993

Patterns of enkephalin immunolabeling in the pulmonate snail Cepaea nemoralis and related molluscs.

In the land pulmonate snail Cepaea nemoralis, immunocytochemical localization of methionine- and leucine-enkephalin-like substances was demonstrated in specific populations of brain neurons. Methionine-enkephalin reactivity is also present in the peripheral nervous system as (i) abundant axonal projections of central neurons to the sole of the foot, and (ii) sparse local neurons of the head and mantle wall. Similar peripheral methionine-enkephalinergic elements were found immunocytochemically in all pulmonates (Helix aspersa, Lymnaea stagnalis) and prosobranchs (Littorina littorea, Acmaea testudinalis) examined and seem therefore conserved among gastropods. Their distribution was different from those of nervous elements labeled by antisera against serotonin and FMRFamide. The chiton Lepidopleurus asellus considered to be a more primitive mollusc, had both types of enkephalin-immunoreactive elements in the central nervous system whereas peripheral methionine-enkephalin-immunoreactive elements were lacking. It is suggested on the morphological evidence that enkephalinergic (especially methionine-enkephalinergic) neurons are part of a sensory system mediating analgetic effects in molluscs.

Animals↗
PubMed1990

Neuronal competition determines the spatial pattern of neuropeptide expression by identified neurons of the leech.

Staining adult and embryonic leech ventral nerve cords with antibodies raised against the molluscan neuropeptides small cardioactive peptide B (SCP) and FMRFamide results in segment-specific and bilaterally asymmetric patterns of cell staining. One immunoreactive neuron, the RAS interneuron, is present in only four rostral segmental ganglia, while another, the CAS interneuron, is restricted to the four most caudal abdominal ganglia and tail. In addition to their segment-specific distributions, only one RAS or CAS cell is found in each segmental ganglion, and they alternate sides between adjacent ganglia (either L-R-L-R or R-L-R-L) with a fidelity of about 95%. This paper utilizes cell deletion techniques to investigate the determination of the asymmetric and alternating pattern of RAS and CAS neurons. We show that developmentally equivalent RAS and CAS homologs are present on both sides of the appropriate ganglia, and that within each ganglion one of the initially paired homologs loses the ability to assume the immunoreactive RAS or CAS fate 2-3 days after axonogenesis has begun. These experiments suggest that there is a competitive interaction between bilateral homologs which ensures that only one mature RAS/CAS neuron is formed per ganglion, and that contralateral RAS/CAS neurons are not required in the same or adjacent ganglia for the determination of the RAS or CAS developmental pathways. Nerve cord transections between ganglia in the CAS domain can alter the spatial pattern of CAS neuron determination, confirming that both bilateral homologs retain the ability to express neuropeptide until late embryonic stages, and suggesting that the alternating pattern of RAS/CAS cells requires communication between adjacent ganglia through the longitudinal connectives.

Animals↗
PubMed1991

A versatile dot-ELISA method with femtomole sensitivity for detecting small peptides.

Several protocols for conjugating peptides in situ to a protein carrier on paper, nitrocellulose, or nylon membranes were explored for their usefulness in dot-ELISA detection of the peptides. The most sensitive method in which peptide diluted in bovine serum albumin is applied to nitrocellulose, then fixed with glutaraldehyde, can detect several peptides, ranging from 4 to 38 amino acids in length, at the level of 2-10 fmol. Both immunohistochemical grade antisera and monoclonal antibodies have been used successfully. The method may be a useful alternative to radioimmunoassay since there is no requirement for radiolabelled peptide, or (for quantitation) for known quantities of unlabelled peptide. The method has been used to monitor, semiquantitatively, the fractionation of FMRFamide-like or CCK-like peptides from the nematode Ascaris, and to detect peptide-like immunoreactivities in tissue extracts.

Animals↗
PubMedDate not supplied

Electrophysiological effects of FLFQPQRF amide, an endogenous brain morphine modulating peptide, on cultured mouse spinal-cord neurons.

Intracellular recordings were made from dissociated fetal mouse spinal cord neurones in primary culture. Micropressure application of FLFQPQRFamide (10(-5) M in the delivery pipette), an endogenous mammalian brain morphine modulating peptide, onto the surface of spinal cord neurones induced, in a dose dependent manner, a transitory hyperpolarization followed by a long lasting depolarization of the membrane potential (n = 37). In contrast, no response was observed when the peptide was applied on dorsal root ganglia neurones (n = 30). The depolarizing phase of this response was underlied by an increase of the input resistance. Extrapolated reversal potential for the depolarizing phase was close to -80 mV while it was close to -40 mV for the hyperpolarizing phase. Increasing extracellular K+ concentration raised the reversal potential value of depolarizing phases to more positive values. The amplitude of the depolarizing phase was reduced by application of tetraethylammonium (50 mM) while it was enhanced by application of 4-aminopyridine (3 mM). CaCl2 application (3 mM) reversibly blocked the hyperpolarization and decreased the subsequent depolarization. In presence of Ba2+ the extrapollated reversal potential of the hyperpolarizing phase was dramatically shifted to a more positive value. Finally FLFQPQRFamide induced response can be partially mimicked by FMRFamide application. Our observations indicate that FLFQPQRFamide can have multiple effects on membrane conductance of mammalian spinal cord neurones by acting on a single class of receptor. These effects of FLFQPQRFamide were found to be mainly excitatory.

Animals↗
PubMed1991

A method for the determination of projection areas of GABA immunoreactive neurons in the invertebrate nervous system.

Axonal transport of metallic salts (nickel or cobalt chloride) has been widely used for the anatomical mapping of neural pathways. We show here that when nickel is introduced into GABAergic neurons it completely eliminates GABA immunolabelling. We have used this property to determine the axonal projections of GABAergic neurons in the stomatogastric system of Crustacea. For example, following nickel backfills from either cut axons or from terminals, GABA immunostaining labels only those GABA-immunoreactive neurons which had not been retrogradely labelled with nickel and hence did not project in the cut nerve or to the neuropile uptake site. By comparing such immunolabelled preparations with those not pretreated with nickel the projection patterns of all the GABA immunoreactive neurons in a given system can be revealed. This effect of nickel appears to be selective for GABA immunostaining, insofar as it does not interfere with the immunodetection of either the peptide proctolin or a FMRFamide-like peptide. This method may prove to be a useful tool for analyzing GABAergic neuronal pathways in the nervous systems of invertebrates.

Animals↗
PubMed1992

In situ hybridization of whole-mounts of Aplysia ganglia using non-radioactive probes.

A protocol for carrying out in situ hybridization with non-radioactive, digoxigenin-labelled probes has been developed for whole-mounts of Aplysia ganglia. Whole-mount preparations preserve the anatomical relationships of neurons within intact ganglia and facilitate the precise identification of a particular neuron in live preparations so that functional studies can be correlated with biochemical attributes of an identified neuron. The protocol was developed with the use of probes to messenger RNAs that are abundant in Aplysia neurons. In situ hybridization with a cDNA probe to a neuronal form of beta-actin stained all neurons, including their processes, whereas use of a cDNA probe for the neuropeptide FMRFamide resulted in staining of a select group of Aplysia neurons.

Actins↗
PubMed1985

Immunocytochemistry of peptidergic systems in the pond snail Lymnaea stagnalis.

Evidence suggests that there exists in the animal kingdom a family of biologically active peptides whose members are related to the molluscan cardio-active tetrapeptide FMRFamide (Phe-Met-Arg-Phe-NH2). Immunocytochemical and ultrastructural studies indicate that several family-members occur in the pond snail Lymnaea stagnalis. Monoclonal antibodies were raised to whole brain homogenates of the pond snail. Selection of antibody producing hybridomas was carried out by staining sections of the central nervous system of the snail with the supernatants of the hybridomas. Certain antibodies stain selectively known (neuro)endocrine centres of the snail, others are directed against particular groups of neurons. It is argued that these antibodies were raised against biologically active peptides and/or their precursors. The antibodies may be used for the isolation of these peptides.

Amino Acid Sequence↗
PubMedDate not supplied

Effects of mammalian FMRF-NH2-related peptides and IgG from antiserum against them on aggression and defeat-induced analgesia in mice.

The effects of two endogenous mammalian FMRFamide (Phe-Met-Arg-Phe-NH2)-related peptides, an octapeptide F8Fa (Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2) and an octadecapeptide A18Fa (Ala-Gly-Glu-Gly-Leu-Ser-Ser-Pro-Phe-Trp-Ser-Leu-Ala-Pro-Gln-Arg-Phe-NH2 ), and IgG from serum against them on the responses to aggression and defeat-induced analgesia were examined in subordinate mice in "resident-intruder" pairings. Intracerebroventricular (ICV) administrations of F8Fa and A18Fa (0.10-10 micrograms) reduced, in a dose-dependent manner, the number of bites to obtain defeat in the subordinate mice during the agonistic encounters, as well as attenuating defeat-induced analgesia, with F8Fa having a greater inhibitory effect than A18Fa. Peripheral administration of naloxone (1.0 mg/kg) had a similar inhibitory effect on the number of bites to defeat and the level of defeat-induced analgesia. In contrast, ICV administrations of F8Fa-IgG and A18Fa-IgG antisera increased the number of bites to defeat and augmented the levels of defeat-induced analgesia, with F8Fa-IgG having a greater effect than A18Fa-IgG. These results provide further evidence that the peptides, F8Fa and A18Fa, are involved in the modulation of opioid-mediated analgesia accompanying biological stressors and suggest that these endogenous FMRF-NH2-related peptides may also be associated with the expression of opioid-sensitive components of aggressive behavior.

Aggression↗
PubMedDate not supplied

NPFF, a FMRF-NH2-like peptide, blocks opiate effects on ileum contractions.

We studied the ability of NPFF, a FMRFamide-like peptide with certain antiopiate properties, to affect the inhibitory effect of morphine on the electrically induced contraction of guinea pig ileum. Neuropeptide FF had no effect when administered alone but reduced morphine inhibition in a noncompetitive manner. Neuropeptide FF also altered the inhibitory effect of opioid peptides as released by an intense electrical stimulation at 10 Hz. These results suggest that NPFF receptors exist in guinea pig ileum in association with opiate receptors, and that endogenous NPFF may play a role in the diarrhea observed in the morphine withdrawal syndrome.

Animals↗
PubMed1996

Receptor inactivation by dye-neuropeptide conjugates: 1. The synthesis of Cys-containing dye-neuropeptide conjugates.

In an attempt to attenuate specifically identified receptors through photolysis, a four-step synthesis is of a useful tethered derivative of Azure-B (Az) was developed After characterization, this derivative was covalently attached to CFMRFamide, CFMRF, and CLRFamide (i.e., three different neuropeptide analogues of the putative neurotransmitter FMRFamide. This resulted in the formation of three dye-neuropeptide conjugates: Az-CFMRFamide, Az-CFMRF, and Az-CLRFamide.

Azure Stains↗
PubMed1987

FMRF-NH2-like factor from neurohaemal organ modulates neuromuscular transmission in the locust.

YGGFMRFamide, FMRFamide and related peptides potentiate transmission at locust slow motor synapses. Since immunohistochemical evidence points to neurohaemal organs (NHO) as potential sources for endogenous RFamide-like peptides we have applied extracts from the metathoracic NHO, equivalent to 1/3 NHO, to the metathoracic extensor tibiae muscle. NHO-extract depolarizes the muscle fibre and increases its membrane resistance; enhances transmitter release; and increases the amplitude of contraction and the rate of relaxation. These effects are in good qualitative and quantitative agreement with those of YGGFMRFamide (5 X 10(-8) to 10(-7) M). Octopamine which partly acts like YGGFMRFamide cannot account for the NHO-effects.

Animals↗
PubMed1995

Inhibitory action of SKPYMRFamide on acetylcholine receptors of Helix aspersa neurons: role of second messengers.

1. SKPYMRFamide, a novel FMRFamide-like endogenous peptide reversibly decreases excitatory responses (depolarization and inward current) evoked by local ionophoretic application of acetylcholine (ACh) onto the soma of identified neurons F1, F2, F4 and F5/6 of the land snail, Helix aspersa. 2. Threshold concentrations of SKPYMRFamide for an inhibitory action on ACh-induced responses are 0.5-1 mumoll-1. This modulatory action of peptide is dose- and time-dependent. 3. It is concluded that SKPYMRFamide inhibits ACh receptors through activation of specific binding sites on the plasma membrane. 4. The possible role of different second messengers in the modulatory influence of SKPYMRFamide on ACh receptors was tested using 13 modulators of different second messenger systems. 5. The results indicate that SKPYMRFamide may inhibit ACh receptors through activation of one or more of the following systems: phospholipases C, A2, NO-synthase, soluble guanylate cyclase and lipoxygenases which elevate basal intracellulal levels of NO, cGMP, arachidonic acid, acyclic eicosanoids, inositol-1,4,5-trisphosphate (I(1,4,5)P3), I(1,4,5)P3-dependent Ca(2+)-mobilization followed by activation of calmodulin and Ca2+/calmodulin-dependent protein kinase II. Protein kinases A, C and cyclic eicosanoids do not appear to participate in modulatory action of SKPYMRFamide.

Acetylcholine↗
PubMed1984

Responses of mouse spinal neurones in culture to locally applied Phe-Met-Arg-Phe-NH2.

Embryonic mouse spinal cord neurones were maintained in a primary dissociated culture with a medium free from antibiotics. Intracellular recordings were made and the effects of local application of the neuropeptide FMRFamide were tested on selected neurones. Two types of response were seen. One response was depolarizing, with an accompanying decrease in conductance. This response was probably caused by a reduction in permeability to potassium ions. The second type of response was accompanied by an increase in conductance. Such responses showed a wide variation in their reversal potentials between different neurones. A combination of permeability changes to sodium and chloride ions appeared to be responsible for these responses.

Animals↗
PubMed1992

Microinjection of the alpha-subunit of the G protein Go2, but not Go1, reduces a voltage-sensitive calcium current.

Calcium currents can be modulated by receptor activation of the GTP-binding protein G(o). We have determined whether the two forms of G(o), Go1 and Go2, differentially regulate calcium current magnitude. Using identified neurons of the pond snail Helisoma, we demonstrate that a high-voltage-activated (HVA) calcium current is reduced by addition of the neuropeptide Phe-Met-Arg-Phe-amide (FMRFamide) and that this inhibition is mediated by a pertussis toxin (PTX)-sensitive G protein pathway. Using this calcium current as an assay for G protein activity, we microinjected GTP gamma S-activated alpha-subunits of G proteins into neuronal somata. We demonstrate that the calcium current is differentially regulated by the two forms of alpha o. Microinjection of alpha o2*, but not alpha o1*, reduces calcium current magnitude.

Amino Acid Sequence↗