| 1. |
- Cervin, Anders
(författare)
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Neuropeptide Y 16-36 inhibits mucociliary activity but does not affect blood flow in the rabbit maxillary sinus in vivo
- 1992
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Ingår i: Regulatory Peptides. - : Elsevier BV. - 1873-1686 .- 0167-0115. ; 39:2-3, s. 237-246
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Tidskriftsartikel (refereegranskat)abstract
- Recent investigations have shown neuropeptide Y (NPY) to be present in the rabbit maxillary sinus, and NPY is known to be released upon sympathetic nerve stimulation. To study, in vivo, the effect on mucociliary activity and blood flow, NPY 1-36 and some of its analogues were injected intra-arterially. The effects of the Y1/Y2 agonist NPY 1-36 was compared with the ones of the Y2 agonist NPY 16-36, the Y1-agonist [Leu31,Pro34]NPY and the Y1/Y2 agonist peptide YY. Mucociliary response was recorded photoelectrically and expressed as a percentage of the basal mucociliary activity immediately prior to challenge. The effect on blood flow was measured with laser Doppler flowmetry and expressed as a percentage of the mean blood flow during the 60 s preceding challenge. NPY 1-36 and NPY 16-36 both reduced mucociliary activity dose-dependently at equimolar dosages (0.024-1.2 nmol/kg). The greatest effect was seen after the highest dosage tested. NPY 1-36 reduced mucociliary activity by 14.6 +/- 1.8%, and NPY 16-36 by 13.2 +/- 1.4%. At the highest dosage tested the Y1 receptor agonist [Leu31,Pro34]NPY did not significantly reduce mucociliary activity, whereas PYY reduced mucociliary activity by 15.0 +/- 1.8%. Injections of NPY 16-36 had no effect on blood flow whereas NPY 1-36, [Leu31,Pro34]NPY and PYY all reduced blood flow dose-dependently. Maximal decrease was seen at the highest dosage tested and was 47.1 +/- 5.4%, 70.4 +/- 7.4% and 58.2 +/- 8.4%, respectively. These findings suggest the mucociliary effects to be mediated via Y2 receptors whereas blood flow is regulated via Y1 receptors.
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| 2. |
- Grundemar, L, et al.
(författare)
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Neuropeptide Y suppresses the neurogenic inflammatory response in the rabbit eye; mode of action
- 1993
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Ingår i: Regulatory Peptides. - : Elsevier BV. - 0167-0115. ; 43:1-2, s. 57-64
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Tidskriftsartikel (refereegranskat)abstract
- Ocular injury in the rabbit causes miosis and breakdown of the blood aqueous barrier (aqueous flare response, AFR), reflecting a sensory nerve-mediated inflammatory response, elicited by the release of tachykinins and calcitonin gene-related peptide (CGRP) from C-fibers. Neuropeptide Y (NPY) occurs in sympathetic fibers in the eye. The study was designed to examine whether NPY and related peptides interfere with the inflammatory response to ocular injury in the rabbit in vivo. The isolated rabbit iris was studied with respect to NPY binding sites and second messenger coupling. The AFR and the miotic response to a standardized injury (infrared irradiation (IR) of the iris) were suppressed dose-dependently by NPY (0.01-1.0 nmol) injected intravitreally 30 min prior the trauma. The treated eye was compared with the contralateral eye, which received 0.9% saline and IR. The Y1 receptor agonist [Pro34]NPY, the Y2 receptor agonist NPY 13-36 and the structurally related peptide YY (1 nmol each) suppressed the AFR in response to IR. Injection of either NPY or the Y1 and Y2 receptor agonists (0.3 nmol each) suppressed the AFR evoked by exogenously applied CGRP (0.15 nmol). Saturation studies with 125I-NPY revealed both high and 'moderate' affinity binding sites in the iris. The Bmax values were 26 and 321 fmol/mg protein, respectively. NPY suppressed the forskolin-stimulated adenylate cyclase activity (IC50 value 19 nM). NPY did not affect basal or noradrenaline-induced accumulation of inositol phosphates in the iris. In conclusion, the rabbit iris seems to be rich in NPY receptors linked to inhibition of adenylate cyclase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 3. |
- Grundemar, L, et al.
(författare)
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Unlike VIP, the VIP-related peptides PACAP, helodermin and helospectin suppress electrically evoked contractions of rat vas deferens
- 1992
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Ingår i: Regulatory Peptides. - : Elsevier BV. - 0167-0115. ; 40:3, s. 331-337
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Tidskriftsartikel (refereegranskat)abstract
- We have compared the effects of vasoactive intestinal peptide (VIP) and of the VIP-related peptides pituitary adenylate cyclase activating peptide (PACAP) 1-27 and 1-38, helodermin, helospectin I and helospectin II, on the electrically evoked twitches in the isolated vas deferens of the rat. While VIP was virtually without effect, PACAP 1-38 suppressed the electrically evoked twitches effectively and in a concentration-dependent manner (pIC50 value 7.5). The naturally occurring N-terminal fragment PACAP 1-27 was less effective than PACAP 1-38 (Imax values 37.2% suppression compared to 76.5%) and less potent. The C-terminal fragment PACAP 16-38 was virtually inactive. Also helodermin and helospectin I+II suppressed the electrically evoked twitches effectively and in a concentration-dependent manner (pIC50 values 6.9; 7.2; 6.8, respectively). The three peptides produced similar maximum reduction of the twitches (74-80%). The findings suggest that PACAP, helodermin and helospectin suppress the electrically evoked contractions in the rat vas deferens via receptors distinct from VIP receptors.
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| 4. |
- Nilsson, Christer, et al.
(författare)
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Distribution of peptidergic nerves in the choroid plexus, focusing on coexistence of neuropeptide Y, vasoactive intestinal polypeptide and peptide histidine isoleucine
- 1990
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Ingår i: Regulatory Peptides. - : Elsevier BV. - 1873-1686 .- 0167-0115. ; 27:1, s. 11-26
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Tidskriftsartikel (refereegranskat)abstract
- Choroid plexus from rat, guinea-pig, rabbit and pig was investigated by light-microscopic immunohistochemistry and by radioimmunoassay for the presence of neuropeptides. A moderately dense supply of nerve fibers containing neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP), respectively, was found around blood vessels and in close relation to the secretory epithelium in both pig and rabbit, while lower densities of nerve fibers were found in rat and guinea-pig. Peptide concentrations ranged from 10-40 pmolequivalents/g (pmoleqv/g) for NPY and 0.5-6 pmoleqv/g for VIP in all four species. Peptide histidine isoleucine (PHI) immunoreactive nerve fibers were present in pig choroid plexus at a lower density than NPY and VIP but with a similar distribution. Low concentrations of substance P (0.3-3 pmoleqv/g) and calcitonin gene-related peptide (0.1-3 pmoleqv/g) were found to a varying degree in choroid plexus tissue from the different species, while immunohistochemical investigation was unable to detect any immunoreactive nerve fibers. NPY was often found to coexist with VIP and PHI in pig choroid plexus, while a lesser amount of nerve fibers showed coexistence of NPY and the noradrenaline synthetizing enzyme, dopamine-beta-hydroxylase. Surgical sympathetic denervation by excision of the superior cervical ganglion in the rabbit abolished NPY-containing nerve fibers, as revealed by immunohistochemistry, but only decreased NPY levels by one third, which may be due to different identity of the peptide being detected by the two techniques. It is concluded that NPY-containing nerve fibers have a dual origin in the choroid plexus and coexist with either noradrenaline or VIP/PHI.
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| 5. |
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| 6. |
- Nilsson, Bengt E, 1949, et al.
(författare)
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VIP-antiserum inhibits fluid secretion by the inflamed gallbladder mucosa.
- 1994
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Ingår i: Regulatory peptides. - 0167-0115. ; 49:3, s. 179-84
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Tidskriftsartikel (refereegranskat)abstract
- The inflammatory fluid secretion by the gallbladder mucosa in experimental cholecystitis is induced by an increased prostaglandin formation and is mediated by intramural nerves. In the present study the effect of VIP-antiserum on the inflammatory fluid secretion in the gallbladder was tested in a validated experimental model in cats. The animals were studied in acute experiments 6 weeks after a procedure when the cystic duct was tied and gallstones were implanted in the gallbladder. During basal conditions there was a continuous secretion of fluid into the lumen of the inflamed gallbladder averaging 0.43 +/- 0.18 ml/h. Injection of VIP antiserum, obtained from immunized rabbits and diluted with saline 1:10 in a bolus of 4 ml into the coeliac artery reversed this secretion into an absorption of 1.72 +/- 0.44 ml h-1 (P < 0.001). VIP-antiserum did not affect the fluid adsorption in control animals with an intact gallbladder and injection of control serum from rabbits not immunized to VIP did not affect fluid secretion in the inflamed gallbladders. The results support the idea that the inflammatory fluid secretion in the gallbladder mucosa is mediated by VIP-ergic nerve fibres.
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