| 1. |
- Andersson, Amelie, et al.
(författare)
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Expression and motor effects of secretin in small and large intestine of the rat
- 2000
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781. ; 21:11, s. 94-1687
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Tidskriftsartikel (refereegranskat)abstract
- Immunocytochemistry and in situ hybridization revealed abundant secretin expressing cells on duodenal villi with a gradual decrease throughout the small intestines of the rat. They were absent in pancreas, stomach and colon. Secretin caused relaxation of rat intestinal longitudinal muscle in vitro. Studies on colon revealed that the secretin-evoked response was unaffected by apamin, tetrodotoxin, L-NAME, VIP or PACAP pretreatment; secretin itself caused desensitization. Addition of VIP or PACAP when the secretin-evoked relaxation was maximal evoked a further relaxation suggesting the presence of distinct receptors. Secretin causes relaxation via activation of secretin receptors located on the smooth muscle and not via any of the related VIP/PACAP receptors.
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| 2. |
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| 3. |
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| 4. |
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| 5. |
- Bungart, D, et al.
(författare)
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Occurrence of analogues of the myotropic neuropeptide orcokinin in the shore crab, Carcinus maenas : evidence for a novel neuropeptide family.
- 1995
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Ingår i: Peptides. - 0196-9781 .- 1873-5169. ; 16:1, s. 67-72
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Tidskriftsartikel (refereegranskat)abstract
- By use of an enzyme immunoassay that was developed for the determination of orcokinin, a myotropic neuropeptide of the sequence NFDEIDRSGFGFN from the crayfish, Orconectes limosus, immunoreactive material was detected in extracts of thoracic ganglia from the shore crab, Carcinus maenas. Isolation of the immunoreactive material was achieved by the following steps: 1) prepurification by gel filtration, 2) immunoaffinity chromatography on an anti-orcokinin IgG protein-A sepharose column, and 3) reversed-phase HPLC. The HPLC profile after affinity purification revealed three main immunoreactive peptides that were rechromatographed. None of these peptides was identical to orcokinin in terms of retention time. Automated gas-phase sequencing revealed these peptides to be analogues of orcokinin differing in one amino acid residue. They were named [Ser9]-, [Ala13]- and [Val13]orcokinin (NFDEIDRSSFGFN, Mr 1549.3; NFDEIDRSGFGFA, Mr 1475.3; NFDEIDRSGFGFV, Mr 1503.9). Carboxypeptidase A treatment of the peptides indicated a free C-terminus. Complete characterization of the three peptides was achieved from approximately 230 thoracic ganglia of Carcinus maenas.
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| 6. |
- Bungart, D, et al.
(författare)
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Quantitative determination and distribution of the myotropic neuropeptide orcokinin in the nervous system of astacidean crustaceans.
- 1994
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 15:3, s. 393-400
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Tidskriftsartikel (refereegranskat)abstract
- For quantitative determinations of orcokinin, an indirect, noncompetitive sandwich ELISA was developed. This ELISA is highly specific for orcokinin and the detection limit is 1 fmol. In three astacidean species (Orconectes limosus, Homarus americanus, and Astacus astacus) orcokinin immunoreactivity (OK-IR) was measurable in all parts of the nervous system. Upon normalization to the protein content of the tissue (pmol/mg protein), concentrations were shown to be in the same range in all three species. The distribution of OK-IR in the nervous system is also very similar in the three species. In Orconectes limosus the following values were obtained (in pmol/mg protein): cerebral ganglion 215, optic ganglia in the eyestalk 38, subesophageal ganglion 182. The thoracic ganglia have lower concentrations (35-72) and the abdominal ganglia (AG) 1-5 even lower ones (11-17). In the AG 6 of Orconectes, from which the innervation of the hindgut arises, concentrations are approximately five times higher than in the other AG. In hindgut tissue, relatively high concentrations of 22 pmol/mg were measured, which is in agreement with the demonstrated function of orcokinin as a hindgut excitatory substance. Markedly elevated levels of orcokinin were observed in the AG 6 of Astacus, but not in Homarus. Orcokinin could also be measured consistently and reliably in the hemolymph, where its concentration is approximately 1 x 10(-11) M. These results show that orcokinin may be released into the hemolymph and may act as a hormone, in addition to its role as a locally acting neurotransmitter/modulator.
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| 9. |
- Dircksen, Heinrich, 1954-, et al.
(författare)
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Structure, distribution, and biological activity of novel members of the allatostatin family in the crayfish Orconectes limosus.
- 1999
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Ingår i: Peptides. - 0196-9781 .- 1873-5169. ; 20:6, s. 695-712
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Tidskriftsartikel (refereegranskat)abstract
- In the central and peripheral nervous system of the crayfish, Orconectes limosus, neuropeptides immunoreactive to an antiserum against allatostatin I (= Dipstatin 7) of the cockroach Diploptera punctata have been detected by immunocytochemistry and a sensitive enzyme immunoassay. Abundant immunoreactivity occurs throughout the central nervous system in distinct interneurons and neurosecretory cells. The latter have terminals in well-known neurohemal organs, such as the sinus gland, the pericardial organs, and the perineural sheath of the ventral nerve cord. Nervous tissue extracts were separated by reverse-phase high-performance liquid chromatography and fractions were monitored in the enzyme immunoassay. Three of several immunopositive fractions have been purified and identified by mass spectroscopy and microsequencing as AGPYAFGL-NH2, SAGPYAFGL-NH2, and PRVYGFGL-NH2. The first peptide is identical to carcinustatin 8 previously identified in the crab Carcinus maenas. The others are novel and are designated orcostatin I and orcostatin II, respectively. All three peptides exert dramatic inhibitory effects on contractions of the crayfish hindgut. Carcinustatin 8 also inhibits induced contractions of the cockroach hindgut. Furthermore, this peptide reduces the cycle frequency of the pyloric rhythms generated by the stomatogastric nervous system of two decapod species in vitro. These crayfish allatostatin-like peptides are the first native crustacean peptides with demonstrated inhibitory actions on hindgut muscles and the pyloric rhythm of the stomatogastric ganglion.
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| 10. |
- Hallberg, Mathias, et al.
(författare)
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Anabolic-androgenic steroids affect the content of substance P and substance P(1-7) in the rat brain
- 2000
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Ingår i: Peptides. - 0196-9781 .- 1873-5169. ; 21:6, s. 845-852
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Tidskriftsartikel (refereegranskat)abstract
- The effects of intramuscular (i.m.) injections of nandrolone decanoate (15 mg/kg/day), an anabolic-androgenic steroid, on the levels of substance P (SP) and on its N-terminal fragment SP(1-7) were examined in the male rat brain by radioimmunoassay. The results demonstrated that the SP immunoreactivity in amygdala, hypothalamus, striatum, and periaqueductal gray was significantly enhanced, whereas the concentration of the N-terminal fragment SP(1-7) was enhanced in the nucleus accumbens and in periaqueductal gray. In the striatum the steroid induced a decrease in the content of SP(1-7). The relevance of these peptides in connection with anabolic-androgenic steroid-induced aggression is discussed.
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