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At least 991 records · Page 55Linked to original sources
PubMed1997

Distribution of neuropeptide Y-like immunoreactivity in the brain of the bichir, Polypterus senegalus, with special regard to the terminal nerve.

The distribution of neuropeptide Y (NPY)-like immunoreactivity in the brain of the bichir, Polypterus senegalus, was examined immunohistochemically. NPY-like immunoreactivity was distributed widely in the brain, with the highest density in the diencephalon. NPY-positive perikarya were found in various areas, including the terminal nerve, the pallial zones of the telencephalon, the periventricular preoptic nucleus, the thalamic nucleus, the ventral hypothalamus of the diencephalon, the tegmentum of the mesencephalon, and the area intermedioventralis of the rhombencephalon. In the hypothalamus, NPY-positive liquor-contacting neurons were frequently observed. Immunoreactive neuron-like cells also appeared in the distal lobe of the hypophysis. NPY fibers were densely distributed in the ventral telencephalon, the hypothalamus, and the ventrolateral area of the rhombencephalon. They were also demonstrated in the terminal nerve. In the hypophysis, NPY fibers were dense in the median eminence, but sparse in the neural lobe. Electron-microscopic double immunostaining of the terminal nerve revealed the coexistence of NPY-like antigen with gonadotropin-releasing hormone-like and molluscan cardioexcitatory tetrapeptide-like antigens in the same cytoplasmic granules. These results suggest that NPY or a related substance is involved in neuroregulation of various areas of the bichir brain, by mainly acting as a neurotransmitter or neuromodulator.

Animals↗
PubMed1997

FMRF amide-like-immunoreactive primary sensory neurons in the olfactory system of the terrestrial mollusc, Limax marginatus.

The distribution of FMRF amide-like immunoreactivity was investigated in the olfactory organs in the tentacle tip of the terrestrial slug, Limax marginatus. Approximately 0.7% of the neurons in the lobules of the tentacle ganglia demonstrated FMRF amide-like immunoreactivity. Most of the FMRF amide-like-immunoreactive somata lay at superficial positions within the lobules, and dendritic processes extended to the outer surface of the sensory epithelium, whereas the axons traveled toward the cerebral ganglion through the ventral part of the tentacle nerve. From their morphological features, FMRF amide-like-immunoreactive cells were considered to be primary sensory neurons.

Animals↗
PubMed1991

APGW-amide as an inhibitory neurotransmitter of Achatina fulica Ferussac.

APGWamide (L-Ala-L-Pro-Gly-L-Trp-NH2) was purified from the ganglia of an African giant snail (Achatina fulica Ferussac). This peptide inhibited (hyperpolarized) more than half of the Achatina neurone types tested. This produced an outward current with the membrane conductance increase of RAPN (right anterior pallial neurone) under voltage clamp. The ED50 of the peptide was 6.2 x 10(-6) M (95% confidence limit: 5.0-7.8 x 10(-6) M) and the Emax was 3.9 +/- 0.2 nA. The effects were due to a membrane permeability increase to K+. The peptide is proposed as an inhibitory neurotransmitter of the Achatina neurones.

Animals↗
PubMed1983

Immunohistochemical studies of FMRF-amide-like immunoreactivity in rat brain.

The anatomical distribution of neuronal perikarya and nerve fibres containing FMRF-amide-like immunoreactivity in the brain, spinal cord and pituitary of the rat has been studied by immunohistochemistry. In animals pretreated with colchicine, the highest concentration of nerve cell bodies occurred in hypothalamic nuclei. Cells were also present in the cortex, striatum, septum, thalamus and in the brainstem. Beaded nerve fibres were abundant in the septum, nucleus of the striae terminalis, hypothalamus, medial regions of the thalamus, the parabrachial nucleus, the ventrolateral medulla, the substantia gelatinosa of the spinal trigeminal nucleus and the dorsal horn of the spinal cord. Fibres were also present in the cortex, striatum, amygdala, pons, ventral spinal cord and the neural lobe of the pituitary. The localization was specific in that preabsorbtion of the antisera with FMRF-amide, but not structurally related molecules such as Met-Enk-Arg6Phe7, APP or BPP, completely abolished the localization. The mammalian counterparts of FMRF-amide may have a neurotransmitter or neuromodulatory role.

Animals↗
PubMed1985

Antibody staining reveals novel aspects of segmentation within the leech central nervous system.

The leech is a segmented annelid with a well characterized central nervous system. In this report, we use antibodies to map the distribution of neurons confined to selected segmental ganglia in the mud leech Haemopis marmorata. The distribution of these neurons suggest 3 novel aspects of segmentation in the leech nervous system: (1) neurons are assigned to even-numbered ganglia through a mechanism which effectively counts through the leech segmental body plan by units of 2, (2) neurons are assigned to ganglia 7 and 14 through a mechanism which effectively counts in units of 7 and (3) neurons are assigned to the 2nd and 4 fused head ganglia and to the 2nd of 21 unfused midbody ganglia through a mechanism which effectively counts units from the origin of these 2 ganglionic series. These 3 hypothetical counting mechanisms divide the central nervous system (CNS) into supersegmental units. Neurons used to define these supersegmental units have been injected with tracer and identified as interganglionic interneurons. Competitive interactions among embryonic precursors of these neurons may directly eliminate their homologs from intervening ganglia, and thus sculpture supersegmental patterns into the mature nervous system.

Animals↗
PubMed1988

Studies of peptidergic input to the lateral spinal nucleus.

Lesions were made to interrupt potential sources of peptidergic input to the lateral spinal nucleus (LSn) in rats. Rhizotomies and spinal transections, as well as lesions of the lateral funiculus, failed to reduce immunohistochemical staining for substance P, dynorphin, Met-enkephalin, somatostatin and FMRF-amide in the LSn at lumbar levels. Thus, all examined peptidergic afferent input to the LSn appears to originate locally within the spinal cord.

Animals↗
PubMed1989

Rat brain regional distribution and spinal cord neuronal pathway of FLFQPQRF-NH2, a mammalian FMRF-NH2-like peptide.

Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2 (F-8-NH2) is a peptide, originally detected by FMRF-NH2 antisera, and subsequently isolated from bovine brain. Using a specific radioimmunoassay for F-8-F-NH2, we have examined the regional distribution and characteristics of F-8-F-NH2 immunoreactivity (IR) in rat brain, spinal cord and pituitary gland. In CNS, F-8-F-NH2-IR is highly concentrated in the spinal cord, hypothalamus and pons-medulla (368, 202 and 136 fmol per mg protein, respectively); lowest values are in the cortex and hippocampus. A modest rostrocaudal gradient of F-8-F-NH2-IR was observed; levels in the sacral cord are 50% higher than in the cervical cord. Dorsal cord content is 8 times higher than in the ventral cord. Dorsal rhizotomy failed to change F-8-F-NH2-IR in the affected regions of the spinal cord while significantly reducing substance P levels. F-8-F-NH2-IR was significantly decreased caudal to a spinal transection, indicating the presence of a descending pathway within the spinal cord. The highest concentration of F-8-F-NH2-IR (1008 fmol per mg protein) was found in the neurointermediate lobe of the pituitary, while no F-8-F-NH2-IR could be detected in the anterior lobe. Immunohistochemically, F-8-F-NH2-IR was confined to nerve terminal-like structures in the neural lobe. The anterior and intermediate lobes were devoid of immunoreactive structures. HPLC characterization of F-8-F-NH2-IR in the dorsal spinal cord, medulla-pons and pituitary revealed one major immunoreactive peak which is more hydrophobic than bovine F-8-F-NH2. In addition to this material, the hypothalamus was found to contain another, more abundant F-8-F-NH2-immunoreactive peak. Analysis of F-8-F-NH2-IR from posterior pituitary with various antisera having differing affinities for F-8-F-NH2 and gamma 1-MSH indicates that the F-8-F-NH2-IR of rat pituitary is not due to gamma 1-MSH. The high concentration of F-8-F-NH2-like peptide in the dorsal spinal cord supports a role in mediating nociceptive transmission while the localization of F-8-F-NH2-IR in the posterior pituitary suggests an additional autonomic or endocrine function.

Animals↗
PubMed1995

A role for calcium/calmodulin-dependent protein kinase in mediating synaptic modulation by a neuropeptide.

The crayfish neuropeptide DRNFLRFamide (DF2) has previously been shown to increase the amplitude of excitatory post-synaptic potentials (EPSPs) in crayfish muscles by enhancing transmitter release from synaptic terminals [18]. This effect involves at least two types of kinase enzyme: one or more kinases which mediate the initial rise in EPSP amplitude, and protein kinase C (PKC) which prolongs the elevation in EPSP amplitude for several minutes [6,7]. The present investigation was aimed at identifying kinases that participate in the initial response. KN-62, an inhibitor of Ca2+/calmodulin-dependent protein kinase, delayed the rise in EPSP amplitude induced by DF2. The maximal response to the peptide occurred in about 40 min when KN-62 was present and in 15 min when the inhibitor was absent. KN-62 did not significantly alter EPSP amplitude by itself. KN-04, a structural analog of KN-62 which does not block Ca2+/CaM kinase activity, did not alter EPSP amplitude or the response to the neuropeptide. These data strongly suggest that Ca2+/CaM kinase participates in the initial increase in transmitter release.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1987

Cell cycles and in vitro transdifferentiation and regeneration of isolated, striated muscle of jellyfish.

Isolated, mononucleated, cross-striated muscle cells of a medusa can transdifferentiate in vitro to various new cell types and even form a complex regenerate. The transdifferentiation events follow a strict pattern. The first new cell type resembles smooth muscle and is formed without a preceding DNA replication. This cell type behaves like a stem cell and by quantal cell cycles produces all other new cell types. Some preparations develop an inner and an outer layer separated by a basal lamella. Formation of these layers does not depend on DNA replication. When layers do not form, each division results in nerve cells and smooth muscle cells. If separation into layers occurs, then a regenerate will be formed, and in the course of only two cell cycles all necessary cell types to form a functional regenerate will differentiate.

Animals↗
PubMed1986

Antiopioid activity of the cardioexcitatory peptide in central modulation of cardiovascular functions.

Intracerebroventricular (i.c.v.) injection of [D-Ala2,Leu5]enkephalin produced depressor and bradycardiac responses which were prevented by naloxone or FMRF-NH2 pretreatment. Intrathecal injection of FMRF-NH2 to rats in hemorrhagic shock resulted in a slight but significant increase in blood pressure, and prevented the further decrease in heart rate which was observed in the control group. It is concluded that FMRF-NH2 may act as an antiopioid substance in central modulation of cardiovascular functions.

Animals↗
PubMed1993

Modulation of neuropeptide effects by achatin-I, an Achatina endogenous tetrapeptide.

Achatin-I (Gly-D-Phe-L-Ala-L-Asp), an endogenous tetrapeptide in the ganglia of Achatina fulica Férussac, at 3 x 10(-6) M suppressed both the inward current (Iin) of an Achatina giant neurone, PON (periodically oscillating neurone), caused by locally ejected oxytocin, and the outward current (Iout) of v-RCDN (ventral-right cerebral distinct neurone) induced by APGW-amide. Dose (pressure duration)-response studies with oxytocin and APGW-amide showed that their ED50 values were not affected by achatin-I, whereas the Emax values were suppressed. The v-RCDN Iout caused by FMRF-amide was enhanced by achatin-I, but the same current induced by [Ser2]Mytilus inhibitory peptide ([Ser2]MIP) was not affected. Achatin-I suppressed the Iout of TAN (tonically autoactive neurone) caused by acetylcholine, but did not affect the Iin of v-RCDN elicited by acetylcholine. The Iout caused by gamma-aminobutyric acid, threo-beta-hydroxy-L-glutamic acid and dopamine was not affected by achatin-I. It is considered that achatin-I acts as a neuromodulator and has both suppressing and enhancing actions on the effects of various neurotransmitters, including peptides, in Achatina giant neurones.

Acetylcholine↗
PubMed1987

Antinociceptive action of cholecystokinin octapeptide (CCK 8) and related peptides in rats and mice: effects of naloxone and peptidase inhibitors.

Cholecystokinin octapeptide (CCK 8) produced significant antinociception in the tail immersion test in the rat, paw pressure test in the rat and acetylcholine-induced writhing test in the mouse after subcutaneous (s.c.) administration. In the hot plate test, CCK 8 (s.c.) showed antinociceptive activity if the latency to lick was used as the end point but if the latency to jump was recorded the antinociceptive effects were not evident. Cholecystokinin tetrapeptide (CCK 4) was shown to be antinociceptive in the writhing but not in the hot plate test after subcutaneous administration and appeared to be less potent than CCK 8 when tested under the same conditions. Antinociception induced by CCK 8 in the hot plate test (lick) could also be demonstrated after direct intracerebroventricular (i.c.v.) injection and this observation was also made with the CCK-related peptide FMRF amide. Antinociception induced by CCK 8 (which did not appear to be associated with reduced locomotor activity) was evident 5 min after intraventricular injection and was maximal at 10 min, the effect lasting over a 30-45 min period. The antinociceptive effect of CCK 8 was antagonised by naloxone and was potentiated by simultaneous administration of the peptidase inhibitors bestatin, thiorphan and captopril.

Animals↗
PubMed1992

A mosquito neuropeptide in a moth larva (Helicoverpa zea): relation to FMRF-amide immunoreactivity.

The cerebral nervous and midgut endocrine systems of the larval corn earworm, Helicoverpa zea, were examined using light microscopy and immunocytochemistry for RF-amide family peptides. Immunoreactivity for a mosquito neuropeptide, Aedes Head Peptide-I (Aea-HP-I,pERPhPSLKTRFa), is widely distributed in this lepidopteran. Immunostaining for Aea-HP-I is localized (1a) in perikarya and axons of the brain, the subesophageal ganglion, and the first thoracic ganglion, (b) in peripheral axons innervating muscles of the midgut, and (2) in numerous midgut endocrine cells. Aea-HP-I-associated activity generally occurs as a subset of FMRF-amide (FMRFa; a molluscan cardioactive peptide) immunoreactivity. Cross-reactivity studies indicate that Aea-HP-I and FMRFa immunoreactivities are heterogeneous in the cerebral nervous system and in axons innervating the muscles of the midgut, but may be homogeneous in midgut endocrine cells. Radioimmunoassay for Aea-HP-I reveals immunoreactivity in hemolymph, as well as in extracts of midguts and heads.

Amino Acid Sequence↗
PubMed1989

Unexpected responses of the obese "cafeteria" rat to the peptide FMRF-amide.

The relationship between the acute effects of FMRF-amide on central monoamines and feeding effects were investigated simultaneously in normophagic and "cafeteria" rats. This tetrapeptide is considered as being representative of an endogenous related peptides family with antagonistic properties on opioid-induced behavioural effects. In normophagic rats, no feeding effect was observed, but there was a decrease in serotonergic metabolism similar to that induced by the classical antagonist, naltrexone. However, in the "cafeteria" rats, FMRF-amide enhanced food intake and increased serotonergic metabolism, exhibiting the classical effects of opiate agonists. Since the effects of FMRF-amide differ according to the ponderal and/or nutritional status, this peptide would appear to act rather as a modulator than a true opiate antagonist on food intake. This raises the question as to the exact role of the recently-discovered endogenous FMRF-amide related family in obesity and/or stimulated feeding patterns.

Animals↗
PubMed1987

Elevation of arterial pressure in rats by two new vertebrate peptides FLFQPQRF-NH2 and AGEGLSSPFWSLAAPQRF-NH2 which are immunoreactive to FMRF-NH2 antiserum.

We found that two recently characterized neuropeptides Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2 (F-8-F-NH2) and Ala-Gly-Glu-Gly-Leu-Ser-Ser-Pro-Phe-Trp-Ser-Leu-Ala-Ala-Pro-Gln-Arg-Phe-NH2 (A-18-F-NH2) elevate mean arterial blood pressure (MAP) in conscious, unrestrained rats. The pressor activities of both agents were attenuated, but not abolished, by prior treatment with guanethidine or prazosin. These results suggest that F-8-F-NH2 and A-18-F-NH2 elevate MAP in rats by potentiating the release of catecholamines and by mechanisms independent of catecholamine release.

Animals↗
PubMed1987

CCK 8 analgesia and hyperalgesia after intrathecal administration in the rat: comparison with CCK-related peptides.

The C-terminal octapeptide of cholecystokinin (CCK 8) was administered intrathecally to rats. Doses in the nanogram range produced weak but significant antinociception in the paw pressure test five minutes after injection whereas microgram doses of CCK 8 produced hyperalgesia. The CCK 8-induced analgesia or hyperalgesia was not seen in the tail flick test and was not associated with motor incapacitation or any other noticeable side effects. The C-terminal tetrapeptide of CCK (CCK 4) and pentagastrin were found to be ineffective in all tests but caerulein and molluscan cardioexcitatory neuropeptide (FMRF-amide), like CCK 8, produced antinociception in the paw pressure test.

Analgesia↗
PubMed1986

Peripheral and central origin of Phe-Met-Arg-Phe-amide immunoreactivity in rat spinal cord.

Phe-Met-Arg-Phe-amide immunoreactivity (FMRF-NH2-IR) is highly concentrated in the dorsal horn of rat spinal cord, and particularly in nerve terminals of lamina I. In order to establish the location of the cell bodies of the lamina I terminals containing FMRF-NH2-IR, we measured by radioimmunoassay the FMRF-NH2-IR in sensory ganglia and in spinal roots. FMRF-NH2-IR was found in both tissues, and reverse-phase HPLC analysis revealed that both tissues contain the same molecular forms that are also present in the spinal cord. Lumbo-sacral rhizotomy induced a 50% decrease of FMRF-NH2-IR in the lumbar segment of the spinal cord suggesting that at least a portion of the FMRF-NH2-IR present in this tissue is of peripheral origin. Transection of the spinal cord at the midthoracic level induced a 20-50% decrease of FMRF-NH2-IR in the lumbar segment of the spinal cord suggesting also the presence of FMRF-NH2-IR in descending pathways.

Animals↗