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Christopher Shaw - One of the best experts on this subject based on the ideXlab platform.

  • Kassina senegalensis skin tachykinins: Molecular cloning of Kassinin and (Thr2, Ile9)-Kassinin biosynthetic precursor cDNAs and comparative bioactivity of mature tachykinins on the smooth muscle of rat urinary bladder
    Biochimie, 2009
    Co-Authors: Lei Wang, Mei Zhou, Laura Lynch, Tianbao Chen, Brian R. Walker, Christopher Shaw
    Abstract:

    Abstract Tachykinins are among the most widely-studied families of regulatory peptides characterized by a highly-conserved C-terminal -Phe-X-Gly-Leu-Met.amide motif, which also constitutes the essential bioactive core. The amphibian skin has proved to be a rich source of these peptides with physalaemin from the skin of Physalaemus fuscomaculatus representing the archetypal aromatic tachykinin (X = Tyr or Phe) and Kassinin from the skin of Kassina senegalensis representing the archetypal aliphatic tachykinin in which X = Val or Ile. Despite the primary structures of both mature peptides having been known for at least 30 years, neither the structures nor organizations of their biosynthetic precursors have been reported. Here we report the structure and organization of the biosynthetic precursor of Kassinin deduced from cDNA cloned from a skin secretion library. In addition, a second precursor cDNA encoding the novel Kassinin analog (Thr2, Ile9)-Kassinin was identified as was the predicted mature peptide in skin secretion. Both transcripts exhibited a high degree of nucleotide sequence similarity and of open-reading frame translated amino acid sequences of putative precursor proteins. The translated preprotachykinins each consisted of 80 amino acid residues encoding single copies of either Kassinin or its site-substituted analog. Synthetic replicates of each Kassinin were found to be active on rat urinary bladder smooth muscle at nanomolar concentrations. The structural organization of both preprotachykinins differs from that previously reported for those of Odorrana grahami skin indicating a spectrum of diversity akin to that established for amphibian skin preprobradykinins.

  • Immunochemical characterisation of tachykinin immunoreactivity in the nervous system of the garden snail, Helix aspersa
    Comparative biochemistry and physiology. C Comparative pharmacology and toxicology, 1992
    Co-Authors: Po Sing Leung, Christopher Shaw, Colin F. Johnston, G.b. Irvine
    Abstract:

    1. Circumoesophageal ganglia and foot muscle of the garden snail. Helix aspersa, were subjected to immunocytochemistry using antisera to the tachykinins, substance P (SP), neurokinin A (NKA), Kassinin (KAS) and eledoisin (ELE). 2. Immunoreactivity in neuronal somata and fibres was detected only with the SP antiserum. 3. SP and NKA radioimmunoassays were performed on extracts of Circumoesophageal ganglia. In common with immunocytochemistry, immunoreactivity was only detected with the SP antiserum. 4. Gel permeation chromatography of extracts resolved a single peak of immunoreactivity eluting slightly later than synthetic mammalian SP. Reverse-phase HPLC of immunoreactive fractions resolved two immunoreactive peptides representing oxidised and reduced forms of a single peptide. 5. These data suggest that the nervous system of H. aspersa contains a single tachykinin with C-tenninal structural characteristics similar to mammalian SP.

Giovanna Improta - One of the best experts on this subject based on the ideXlab platform.

  • In vitro and in vivo biological activities of PG-KII, a novel Kassinin-like peptide from the skin of the Australian frog, Pseudophryne güntheri
    Peptides, 1996
    Co-Authors: Giovanna Improta, Cinzia Severini, Maria Broccardo, Vittorio Erspamer
    Abstract:

    Abstract We compared the in vitro and in vivo biological activities of PG-KII (pGlu-Pro-Asn-Pro-Asp-Glu-Phe-Val-Gly-Leu-Met-NH 2 ), a new peptide belonging to the tachykinin family, related to Kassinin, isolated and sequenced from extracts of the skin of the Australian myobatrachid frog Pseudophryne guntheri , with those of the well-known tachykinins [substance P (SP), neurokinin A (NKA), neurokinin B (NKB), and Kassinin (KASS)] to study its pharmacological and receptor profile. PG-KII always proved inactive in the in vitro and in vivo (gastric emptying) NK 2 bioassays. It resulted equipotent to SP and more potent than KASS, NKA, and NKB in all in vitro smooth muscle preparations preferentially activated by the NK 1 -selective agonists. On an in vivo NK 3 receptor-mediated function, gastric acid secretion, PG-KII had a potency similar to that of NKB. In contracting guinea pig ileum, which contains NK 1 , NK 2 , NK 3 , and also new tachykinin receptor subtypes, PG-KII was more potent than SP, NKB, and NKA. The cholinergic antagonist, atropine, significantly reduced the guinea pig contractile activity of both PG-KII and NKB but not that of SP or NKA. Pretreatment with the NK 1 -selective antagonist, CP 96,345, and with the NK 2 -selective antagonist, MEN 10,376, modified neither the in vivo nor the in vitro effects of PG-KII. These findings indicate that PG-KII is neither an NK 1 nor an NK 2 receptor agonist but has a spectrum of biological actions close to that of the NK 3 receptor agonists. PG-KII elicits strong contractile activity in guinea pig ileum. Administered centrally in the rat it regulates inhibition of gastric acid secretion.

  • Effect of PG-SPI and PG-KII, two novel and natural tachykinins, on salivary secretion in the rat
    Peptides, 1996
    Co-Authors: Maria Broccardo, Giovanna Improta, A. Brandoni, Alessandra Tabacco
    Abstract:

    Abstract In an in vivo study of salivation in rats, the scialogogic effects of two natural and amphibian tachykinins, PG-SPI and PG-KII, which activate distinct tachykinin receptors, were compared with those of the tachykinins substance P, neurokinin A and B, and Kassinin. The rank order of potencies of these peptides injected intravenously on salivation was: PG-SPI = SP ≥ PG-KII = KASS > NKA ⪢ NKB. Atropine (1 mg/kg, IV) had no effect on PG-SPI-, SP-, and NKA-induced salivation, but reduced that stimulated by PG-KII and KASS. We conclude that PG-SPI and PG-KII increase salivary secretion through different mechanisms and that rat salivary glands contain PG-SPI- and PG-KII-sensitive receptors.

  • Effect of PG-SPI and PG-KII, two novel and natural tachykinins, on salivary secretion in the rat
    'Elsevier BV', 1996
    Co-Authors: Maria Broccardo, Giovanna Improta, A. Brandoni, Alessandra Tabacco
    Abstract:

    In an in vivo study of salivation in rats, the scialogogic effects of two natural and amphibian tachykinins, PG-SPI and PG-KII, which activate distinct tachykinin receptors, were compared with those of the tachykinins substance P, neurokinin A and B, and Kassinin. The rank order of potencies of these peptides injected intravenously on salivation was: PG-SPI = SP greater than or equal to PG-KII = KASS > NKA >> NKB. Atropine (1 mg/kg, IV) had no effect on PG-SPI-, SP-, and NKA-induced salivation, but reduced that stimulated by PG-KII and KASS. We conclude that PG-SPI and PG-KII increase salivary secretion through different mechanisms and that rat salivary glands contain PG-SPI- and PG-KII-sensitive receptors

Maria Broccardo - One of the best experts on this subject based on the ideXlab platform.

  • In vitro and in vivo biological activities of PG-KII, a novel Kassinin-like peptide from the skin of the Australian frog, Pseudophryne güntheri
    Peptides, 1996
    Co-Authors: Giovanna Improta, Cinzia Severini, Maria Broccardo, Vittorio Erspamer
    Abstract:

    Abstract We compared the in vitro and in vivo biological activities of PG-KII (pGlu-Pro-Asn-Pro-Asp-Glu-Phe-Val-Gly-Leu-Met-NH 2 ), a new peptide belonging to the tachykinin family, related to Kassinin, isolated and sequenced from extracts of the skin of the Australian myobatrachid frog Pseudophryne guntheri , with those of the well-known tachykinins [substance P (SP), neurokinin A (NKA), neurokinin B (NKB), and Kassinin (KASS)] to study its pharmacological and receptor profile. PG-KII always proved inactive in the in vitro and in vivo (gastric emptying) NK 2 bioassays. It resulted equipotent to SP and more potent than KASS, NKA, and NKB in all in vitro smooth muscle preparations preferentially activated by the NK 1 -selective agonists. On an in vivo NK 3 receptor-mediated function, gastric acid secretion, PG-KII had a potency similar to that of NKB. In contracting guinea pig ileum, which contains NK 1 , NK 2 , NK 3 , and also new tachykinin receptor subtypes, PG-KII was more potent than SP, NKB, and NKA. The cholinergic antagonist, atropine, significantly reduced the guinea pig contractile activity of both PG-KII and NKB but not that of SP or NKA. Pretreatment with the NK 1 -selective antagonist, CP 96,345, and with the NK 2 -selective antagonist, MEN 10,376, modified neither the in vivo nor the in vitro effects of PG-KII. These findings indicate that PG-KII is neither an NK 1 nor an NK 2 receptor agonist but has a spectrum of biological actions close to that of the NK 3 receptor agonists. PG-KII elicits strong contractile activity in guinea pig ileum. Administered centrally in the rat it regulates inhibition of gastric acid secretion.

  • Effect of PG-SPI and PG-KII, two novel and natural tachykinins, on salivary secretion in the rat
    Peptides, 1996
    Co-Authors: Maria Broccardo, Giovanna Improta, A. Brandoni, Alessandra Tabacco
    Abstract:

    Abstract In an in vivo study of salivation in rats, the scialogogic effects of two natural and amphibian tachykinins, PG-SPI and PG-KII, which activate distinct tachykinin receptors, were compared with those of the tachykinins substance P, neurokinin A and B, and Kassinin. The rank order of potencies of these peptides injected intravenously on salivation was: PG-SPI = SP ≥ PG-KII = KASS > NKA ⪢ NKB. Atropine (1 mg/kg, IV) had no effect on PG-SPI-, SP-, and NKA-induced salivation, but reduced that stimulated by PG-KII and KASS. We conclude that PG-SPI and PG-KII increase salivary secretion through different mechanisms and that rat salivary glands contain PG-SPI- and PG-KII-sensitive receptors.

  • Effect of PG-SPI and PG-KII, two novel and natural tachykinins, on salivary secretion in the rat
    'Elsevier BV', 1996
    Co-Authors: Maria Broccardo, Giovanna Improta, A. Brandoni, Alessandra Tabacco
    Abstract:

    In an in vivo study of salivation in rats, the scialogogic effects of two natural and amphibian tachykinins, PG-SPI and PG-KII, which activate distinct tachykinin receptors, were compared with those of the tachykinins substance P, neurokinin A and B, and Kassinin. The rank order of potencies of these peptides injected intravenously on salivation was: PG-SPI = SP greater than or equal to PG-KII = KASS > NKA >> NKB. Atropine (1 mg/kg, IV) had no effect on PG-SPI-, SP-, and NKA-induced salivation, but reduced that stimulated by PG-KII and KASS. We conclude that PG-SPI and PG-KII increase salivary secretion through different mechanisms and that rat salivary glands contain PG-SPI- and PG-KII-sensitive receptors

Giuseppe Cassano - One of the best experts on this subject based on the ideXlab platform.

  • Eledoisin and Kassinin, but not EnteroKassinin, stimulate ion transport in frog skin
    Peptides, 2004
    Co-Authors: Claudio Lippe, Vito Bellantuono, C. Ardizzone, Giuseppe Cassano
    Abstract:

    In frog skin, tachykinins stimulate the ion transport, estimated by measuring the short-circuit current (SCC) value, by interacting with NK1-like receptors. In this paper we show that Kassinin (NK2 preferring in mammals) increases the SCC, while EnteroKassinin has no effect. Therefore, either 2 Pro residues or 1 Pro and 1 basic amino acid must be present in the part exceeding the C-terminal pentapeptide. Eledoisin (NK3 preferring in mammals) stimulation of SCC is reduced by CP99994 and SR48968 (NK1 and NK2 antagonists) and not affected by SB222200 (NK3 antagonist). None of the three antagonists affects Kassinin stimulation of SCC.

  • Actions of tachykinins on the ion transport across the frog skin
    Peptides, 1998
    Co-Authors: Claudio Lippe, Vito Bellantuono, Giuseppe Cassano, Simona Lobasso, C. Ardizzone
    Abstract:

    Abstract The tachykinin-dependent stimulation of ion transport across frog skin was studied. Tachykinin stimulation was due to interaction with an NK1-like receptor as [Sar9-Met(O2)11]-Substance P (a very selective NK1 agonist) strongly stimulated SCC, whereas [β-Ala8]-Neurokinin A 4–10 (a very selective NK2 agonist) did not. The rank order of tachykinin potency was: PG-KI > Uperolein > Hylambatin > Kassinin > Phyllomedusin > [Sar9-Met (O2)11]-Substance P > Ranatachykinin A > Physalaemin > Ranakinin > Substance P and Eledoisin ≫ Neurokinin A. Neurokinin B, Scyliorhinin I, Urechistachykinin I and Urechistachykinin II had no effect. We conclude that the minimal structural requirements for stimulating SCC in the frog skin were the presence of: a) the C-terminal sequence Phe-X-Gly-Leu-Met-NH2; b) at least one Pro residue in the N-terminal sequence.

  • Action of capsaicin and related peptides on the ionic transport across the skin of Rana esculenta.
    Archives internationales de physiologie de biochimie et de biophysique, 1994
    Co-Authors: Claudio Lippe, Vito Bellantuono, C. Ardizzone, G Castronuovo, Giuseppe Cassano
    Abstract:

    Capsaicin at low concentrations increases the short circuit current (SCC) across frog skin. Simultaneous measurements of both transepithelial fluxes of 22Na or 36Cl demonstrate that the SCC increase is due to stimulation of sodium active absorption. Capsaicin acts through the liberation of several peptides; thus these peptides were tested on the SCC across frog skin. Those more active are, in order of potency: Cyclic Calcitonin Gene Related Peptide (CGRP), Kassinin and Eledoisin, Substance P (SP) and Neurokinin A. Neurokinin B and Vasoactive Intestinal Peptide (VIP) have no effect. Also the actions of SP and CGRP are due mainly to stimulation of Na+ active absorption. A strict parallelism regarding the sensitivity to inhibitors (Naproxen, SQ22536 and CP96345) between SP, CGRP and Capsaicin strengthens the hypothesis that SP and CGRP are liberated by Capsaicin in this tissue.

Elizabeth Burcher - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of receptors for two Xenopus gastrointestinal tachykinin peptides in their species of origin
    Naunyn-Schmiedeberg's Archives of Pharmacology, 2004
    Co-Authors: Ågot Johansson, Lu Liu, Susanne Holmgren, Elizabeth Burcher
    Abstract:

    Two tachykinin peptides, bufokinin and Xenopus neurokinin A (X-NKA) were recently isolated from Xenopus laevis . In this study we investigated the tachykinin receptors in the Xenopus gastrointestinal tract. In functional studies using stomach circular muscle strips, all peptides had similar potencies (EC_50 values 1–7 nM). The rank order of potency to contract the intestine was physalaemin (EC_50 1 nM)≥bufokinin (EC_50 3 nM)>substance P (SP)≥cod SP>NKA>>X-NKA (EC_50 1,900 nM). No maximum response could be obtained for [Sar^9,Met(O_2)^11]SP, eledoisin and Kassinin. In stomach strips, the mammalian tachykinin receptor antagonists RP 67580 (NK1) and MEN 10376 (NK2) had agonistic effects but did not antagonize bufokinin or X-NKA. In intestinal strips, RP 67580 (1 μM) reduced the maximal response to X-NKA but not bufokinin, while MEN 10376 was ineffective. [^125I]BH-bufokinin bound with high affinity to a single class of sites, of K_D 213±35 (stomach) and 172±9.3 pM (intestine). Specific binding of [^125I]BH-bufokinin was displaced by bufokinin≥SP>NKA≥eledoisin≈Kassinin>X-NKA, indicating binding to a tachykinin NK1-like receptor. Selective tachykinin receptor antagonists were weak or ineffective. Other iodinated tachykinins ([^125I]NKA and [^125I]BH-eledoisin) displayed biphasic competition profiles, with the majority of sites preferring bufokinin rather than X-NKA. In conclusion, there is evidence for two different tachykinin receptors in Xenopus gastrointestinal tract. Both receptors may exist in stomach, whereas the bufokinin-preferring NK1-like receptor predominates in longitudinal muscle of the small intestine. Antagonists appear to interact differently with amphibian receptors, compared with mammalian receptors.

  • Predominantly to NK1 Receptors in Guinea Pig Lung
    1991
    Co-Authors: Radioiodinated Substance P, Neurokinin A, Eledoisin Bind, Dominic P. Geraghty, Christian J. Mussap, Elizabeth Burcher
    Abstract:

    In homogenates of guinea pig lung, binding of 1251-Bolton-Hunter-labeled substance P (BHSP), Bolton-Hunter-labeled eledoisin (BHELE), and [1251]iodohistidyl neurokinin A (INKA) was investi-gated. Equilibrium dissociation constants (derived from “cold” saturation experiments) for BHSP, INKA, and BHELE were 0.96 ± 0.1 5, 1.61 ± 0.26, and 1.98 ± 0.1 2 flM, respectively. Specific binding of all three radioligands was increased 2-3-fold by 10 zM phosphoramidon. The rank order of potency of unlabeled tachykinins in competing against BHSP was substance P (SP)> [Sar,Met(O2)”]-SP> SP methyl ester> neuropeptide-y> neurokinin A neurokinin B = Kassinin eledoisin> scyliorhinin II>> neuropeptide K, indicating binding to sites with the general characteristics of NK1 receptors. Similar rank potency orders were observed for INKA and BHELE, showing binding to NK1 sites, rather than to NK2 or NK3 sites, which are labeled wit