Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ca2+ ionophores (A23187 and ionomycin) were used to determine whether an increase in cytosolic Ca2+ plays a direct role in pig coronary endothelial cell hyperpolarization. Ionophores induced concentration-dependent hyperpolarizations that were not altered by the presence of N omega-nitro-L-argnine (L-NNA), and inhibitor of nitric oxide synthesis. d-Tubocurarine decreased by 65-89% the A23187- and substance P (SP)-generated hyperpolarization of endothelial cells. To study the role of endothelial cell hyperpolarization in the endothelium-dependent relaxation of precontracted coronary artery strips, A23187 and SP concentration-response curves were built up in the presence of d-tubocurarine and/or L-NNA. A decrease in the maximal response was observed only when both d-tubocurarine and L-NNA were present. Our direct in situ approach gives results in agreement with a gating of Ca(2+)-activated K+ channels during A23187- and SP-induced hyperpolarizations of endothelial cells. We suggest that these hyperpolarizations play a role in the endothelial cell-dependent relaxation induced by A23187 and SP in the pig coronary artery.
 ...
PMID:Effect of Ca2+ ionophores on membrane potential of pig coronary artery endothelial cells. 137 77

1. The aim of this study was to characterize the neurokinin receptor which mediates relaxation of dog isolated middle cerebral artery by the use of selective agonists and antagonists and to establish whether substance P is involved in the neurogenically mediated relaxant response in this vessel. 2. Substance P caused concentration-related, endothelium-dependent relaxations of dog isolated middle cerebral artery, contracted with prostaglandin F2 alpha. The selective NK1 receptor agonists, GR73632 and substance P methyl ester (SPOMe), also caused relaxation with similar maximum effects to those of substance P. GR73632 and SPOMe were approximately 20 times and 6 times less potent respectively than substance P. The selective NK2 and NK3 receptor agonists, GR64349 and senktide, were only weakly active in causing relaxation being at least 425 times and 245 times less potent respectively than substance P. 3. The selective NK1 receptor antagonist, GR82334, was a potent, specific, competitive antagonist of the relaxant effects of substance P. In contrast, the selective NK2 receptor antagonist, R396 (10 microM) had no effect on the response to substance P. 4. Electrical field stimulation of dog isolated middle cerebral artery, contracted with prostaglandin F2 alpha, caused neurogenically mediated, non-adrenergic non-cholinergic (NANC) relaxations. These NANC relaxations were unaffected by endothelium removal, GR82334 (10 microM) or by capsaicin (10 microM) treatment. However, the nitric oxide synthesis inhibitor, L-NG-monomethyl arginine methyl ester (L-NMMA) (100 microM) markedly attenuated the response to electrical stimulation. 5. These results suggest that substance P causes relaxation of dog isolated middle cerebral artery via activation of NK1 receptors. However, substance P does not appear to be involved in NANC neurotransmission. In contrast, the marked inhibitory effect of L-NMMA on NANC relaxations implicates nitric oxide in NANC neurotransmission in this vessel.
 ...
PMID:Characterization of the receptor mediating relaxation to substance P in canine middle cerebral artery: no evidence for involvement of substance P in neurogenically mediated relaxation. 138 Mar 74

Interleukin-1 receptor antagonist (IRA) is a secretory product of human monocytes or related cell lines that acts as a pure interleukin-1 (IL-1) antagonist in several bioassays. IRA administration was reportedly a life-saving intervention in rabbits injected with lethal doses of bacterial lipopolysaccharide (LPS). We report the inhibitory effect of IRA on three distinct types of vascular responses to IL-1 in rabbit isolated blood vessels. The rabbit isolated superior mesenteric artery, when precontracted with phenylephrine, relaxed in a sustained manner in less than 30 min following application of recombinant interleukin-1 beta (12-290 pM), and this was a prostaglandin (PG)-dependent and endothelium-independent process. IRA (human recombinant sequence; 0.9-15 nM) behaved as an antagonist of IL-1 alpha or IL-1 beta, based on the surmountability and the concentration dependence, but could only prevent the effect of IL-1, not reverse it. IRA had no direct effect on the preparation and did not influence the acute relaxing effect elicited by substance P or iloprost, a PGI2 mimetic. Exposure to IL-1 beta depressed the response to noradrenaline (NA) in several hours in rabbit aorta rings. The inhibitory effect of IL-1 beta was endothelium and prostaglandin independent, but was prevented by a treatment with NG-nitro-L-arginine (a nitric oxide synthesis inhibitor), cycloheximide, dexamethasone, or IRA. Using the residual NA-induced contraction as a quantification of the IL-1 agonist effect, IRA was a very potent antagonist of IL-1 beta but was not totally surmountable.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effects of interleukin-1 receptor antagonist on three types of responses to interleukin-1 in rabbit isolated blood vessels. 138 81

We investigated the possibility of nitric oxide (NO), a powerful vasodilator agent, being synthesized by perivascular nerve fibres. Immunoreactivity and catalytic activity of the NO synthesizing enzyme, NO synthase (NOS), were demonstrated in perivascular nerve fibres of blood vessels receiving autonomic vasodilator innervation, but not of those innervated exclusively by vasoconstrictor nerve fibres. Double-labelling techniques allowed identification of NOS-containing nerve fibres as belonging to the vasoactive intestinal peptide (VIP)/acetylcholine-containing class whereas noradrenergic and substance P-containing perivascular fibres were devoid of NOS. We suggest that, in addition to its endothelial source, NO is a neuronal co-mediator of VIP/cholinergic vasodilation.
 ...
PMID:Nitric oxide synthase in VIP-containing vasodilator nerve fibres in the guinea-pig. 138 69

1. The effects of L-NG-nitroarginine (L-NOARG) and L-NG-nitroarginine methyl ester (L-NAME) on vasodilatation induced by ATP, substance P, 5-hydroxytryptamine (5-HT), bradykinin and sodium nitroprusside (SNP) were examined in the guinea-pig coronary bed, by use of a Langendorff technique. The effects of these inhibitors of nitric oxide synthesis were assessed on their ability to inhibit both the amplitude and the area of the vasodilator response. 2. The vasodilator responses evoked by low doses of 5-HT (5 x 10(-10)-10(-8) mol) were almost abolished by L-NAME and L-NOARG (both at 10(-5), 3 x 10(-5) and 10(-4) M), although L-NOARG (3 x 10(-5) M) was significantly less potent than L-NAME (3 x 10(-5) M) as an inhibitor of vasodilator responses to 5-HT (5 x 10(-8) mol). 3. The vasodilator responses evoked by substance P (5 x 10(-12)-5 x 10(-9) mol) were reduced in the presence of L-NAME and L-NOARG (both at 10(-5) and 3 x 10(-5) M). The response to substance P was almost abolished by L-NAME and L-NOARG (both at 10(-4) M). 4. The amplitude of the vasodilator responses to ATP (5 x 10(-11) and 5 x 10(-9)-5 x 10(-7) mol) was little affected by either L-NAME or L-NOARG (both at 10(-5), 3 x 10(-5) and 10(-4) M).7. It is concluded that in the guinea-pig coronary vasculature, the vasodilatation evoked by substance P and low doses of 5-HT is mediated almost exclusively via nitric oxide, whereas the vasodilatations evoked by ATP and bradykinin appear to involve other mechanisms in addition to the release of nitric oxide. L-NAME was a more effective agent than L-NOARG in inhibiting the vasodilator actions of 5-HT and ATP in this preparation.
 ...
PMID:Effects of nitric oxide synthase inhibitors, L-NG-nitroarginine and L-NG-nitroarginine methyl ester, on responses to vasodilators of the guinea-pig coronary vasculature. 138 16

AE0047, a new dihydropyridine-type Ca2+ entry blocker, significantly inhibited the contractions induced by transmural electrical stimulation and norepinephrine in dog mesenteric artery strips. The inhibition was greater in the case of the response to nerve stimulation. The 3H-overflow ratio evoked by electrical stimulation from strips previously soaked in [3H]norepinephrine was significantly reduced by AE0047 but not by nicardipine in a concentration sufficient to attenuate the response to norepinephrine. In aorta homogenate preparations, [3H]bunazosin binding was not replaced by AE0047 but by phentolamine. In strips treated with indomethacin, the endothelium-dependent relaxation caused by substance P and bradykinin was attenuated by treatment with AE0047 but not with nicardipine. The nitric oxide (NO)-induced relaxation was not influenced by AE0047. Cyclic GMP levels in the artery strips increased in response to substance P; the increase was markedly suppressed by AE0047 but not by nicardipine. In contrast to nicardipine, AE0047 appeared to inhibit the release of norepinephrine from adrenergic nerves and of NO from endothelial cells. The inhibition may be associated with the decreased transmembrane influx of Ca2+ in these tissues.
 ...
PMID:AE0047, a new dihydropyridine Ca2+ entry blocker, inhibits the responses to adrenergic nerve stimulation and substance P in dog mesenteric arteries. 138 79

Recent studies suggest endothelium to be involved in the vasorelaxation of calcium antagonists of the 1,4-dihydropyridine type, which may at least in part be mediated by endothelium-derived relaxing factor (EDRF = NO). To study this effect further, the influence of L-NG-nitro arginine (L-NNA), a specific inhibitor of EDRF-synthesis, on nitrendipine-induced vasorelaxation was examined in different isolated porcine arteries. Coronary, basilary, and tail arteries were bathed in Krebs-Henseleit solution and endothelial function was verified by means of substance P, an EDRF releasing neuropeptide. Vasorelaxation of nitrendipine in PGF2 alpha-precontracted arteries was studied in the presence and absence of L-NNA. Nitrendipine-induced vasorelaxation was markedly reduced by the addition of L-NNA in all vessels studied. Tachyphylactic effects of nitrendipine could be excluded. The obtained results may be explained by an enhancement of nitrendipine action by basally released EDRF, alternatively, by an increased EDRF-release induced by this calcium antagonist. Therefore, in a second series of experiments the release of EDRF was studied in isolated coronary arteries under cumulative application of nitrendipine. Using the nitric oxide scavenging properties of oxyhemoglobin, EDRF release was measured spectrophotometrically by means of methemoglobin formation. The application of nitrendipine resulted in a concentration-dependent increase in the extinction rate, indicating an increased release of NO which could be inhibited by preincubation with L-NNA. It may be concluded that, in functionally intact vessels, vasorelaxation induced by nitrendipine may additionally be mediated by an increased release of EDRF.
 ...
PMID:Nitric oxide (EDRF) enhances the vasorelaxing effect of nitrendipine in various isolated arteries. 146 29

We investigated the influence of exogenously administered acetylcholine, nitric oxide, ADP, ATP, bradykinin, and substance P on coronary vascular tone in isolated, neonatal pig hearts (less than or equal to 4 d). Paced (180 bpm), isovolumically beating hearts underwent retrograde aortic perfusion, with an erythrocyte-enriched solution (hematocrit 0.15-0.20) at constant coronary flow (approximately 2.5 mL/min/g) corresponding to a perfusion pressure of approximately 60 mm Hg. Agonists were injected into the aortic root, and the peak change in coronary perfusion pressure from baseline and left ventricular pressure development were assessed. Nitric oxide (3 microL), ADP (30 nmol), ATP (30 nmol), bradykinin (125 ng), and substance P (50 ng) decreased the perfusion pressure (vasodilation) by 16.9 +/- 1.2, 25.3 +/- 4.4, 18.3 +/- 1.2, 18.9 +/- 1.4, and 7.1 +/- 1.6 mm Hg, respectively. Acetylcholine (0.5 and 1.0 nmol) produced a modest decrease in perfusion pressure (vasodilatation) of 4.2 +/- 0.8 and 3.8 +/- 0.5 mm Hg, respectively, whereas acetylcholine (5, 20, and 100 nmol) increased the perfusion pressure (vasoconstriction) by 16.7 +/- 2.7, 48.2 +/- 8.2, and 85.3 +/- 15.1 mm Hg, respectively. Acetylcholine also decreased left ventricular peak systolic pressure from 108.7 +/- 5.0 to 69.2 +/- 4.6, 56.3 +/- 6.1, and 48.2 +/- 6.4 mm Hg, for the 5, 20, and 100 nmol doses, respectively. Responses to acetylcholine were abolished by atropine (50 nmol). In a separate group of hearts, indomethacin (10(-6) M) reduced the peak change in perfusion pressure for the 5, 20, and 100 nmol doses of acetylcholine by 87%, 66%, and 48%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Acetylcholine-induced coronary vasoconstriction and negative inotropy in the neonatal pig heart. 150 17

Effects of selective (nicardipine) and nonselective (Cd++) Ca++ channel antagonists on the responses of isolated dog cerebral arteries to vasodilator nerve stimulation, substance P, serotonin and prostaglandin F2 alpha were investigated; the relaxation caused by the nerve stimulation and the peptide is mediated by NO, possibly from the nerve and endothelium, respectively. Relaxant responses to nerve stimulation by electrical pulses and nicotine in the endothelium-denuded arteries were attenuated by Cd++, but not influenced by nicardipine; the concentrations of these antagonists were sufficient to suppress contractions caused by prostaglandin F2 alpha and serotonin to a similar extent. Increase in cyclic GMP by nicotine was also suppressed solely by Cd++. In the endothelium-intact arteries treated with indomethacin, relaxations induced by substance P were not affected by nicardipine, but were significantly attenuated by Cd++. The peptide-induced increase in cyclic GMP was suppressed by Cd++, but not by nicardipine. It is concluded that functional properties of the Ca++ channel responsible for increasing cytosolic Ca++ in the nerve and endothelium for the synthesis and release of nitric oxide or endothelium-derived relaxing factor differ from those of the channel in smooth muscle. Because Ca++ is a prerequisite for the synthesis of NO, smooth muscle does not appear to be the site of production of NO that transmits vasodilator information from the nerve or endothelium to cerebroarterial smooth muscle.
 ...
PMID:Different susceptibility of vasodilator nerve, endothelium and smooth muscle functions to Ca++ antagonists in cerebral arteries. 156 Mar 70

Transmural electrical stimulation and nicotine produced a relaxation of dog cerebral artery strips denuded of endothelium, which was abolished by tetrodotoxin and hexamethonium, respectively, and also suppressed by treatment with NG-nitro-L-arginine (L-NA), a nitric oxide (NO) synthesis inhibitor. The inhibition was reversed by L-arginine but not by the D-enantiomer. L-NA also suppressed the endothelium-dependent relaxation by substance P but not the response to NO and nitroglycerin. Treatment with high concentrations of nitroglycerin or sodium nitroprusside markedly inhibited the relaxant response to nicotine, substance P and NO but not the response to papaverine. Slight, slowly developing relaxations caused by L-arginine in the endothelium-denuded arteries were not potentiated by repeated applications of the amino acid or by exposure of the strips for 24 hr to the bathing medium. Ca++ ionophore-induced contractions in the denuded strips were not potentiated by L-NA. Nicotine significantly increased the level of cyclic GMP in the arteries without endothelium; the increment was abolished by treatment with L-NA and hexamethonium. NO does not seem to be synthesized in smooth muscle in an amount sufficient to produce significant relaxation. It may be concluded that NO liberated from vasodilator nerves activates guanylate cyclase in smooth muscle and produces cyclic GMP, resulting in cerebroarterial relaxation.
 ...
PMID:Role of nitric oxide in neurally induced cerebroarterial relaxation. 165 33


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>