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Query: UNIPROT:P20366 (
substance P
)
21,176
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The effect of the phorbol ester phorbol-12,13-dibutyrate (PDB), an activator of
protein kinase C
, on endothelium-dependent relaxation was studied in noradrenaline-constricted isolated aortic ring preparations of the rabbit. Endothelium-dependent relaxation induced by acetylcholine or
substance P
was inhibited by PDB (greater than or equal to 10(-7) M). Endothelium-dependent relaxation induced by the calcium ionophore A23187 (7.5 X 10(-8) and 10(-7) M) was unaffected by PDB (to 10(-6) M). The mechanical responses to acetylcholine or sodium nitroprusside in endothelium-denuded rings were not altered by PDB (to 10(-6) M). The results suggest a role for
protein kinase C
in receptor-mediated EDRF release mechanisms.
...
PMID:A phorbol ester inhibits the release of endothelium-derived relaxing factor. 311 69
We have used digitonin permeabilization to study the mechanism of bombesin-induced activation of
protein kinase C
in Swiss 3T3 cells. Protein kinase C-mediated phosphorylations in permeabilized cells were identified using phorbol esters and diacylglycerols. Addition of phorbol 12,13-dibutyrate (PDBu) in the presence of [gamma-32P]ATP and digitonin caused a marked and rapid time- and dose-dependent increase in the phosphorylation of an Mr 80,000 cellular protein (maximum stimulation = 12.6 +/- 1.6-fold after 1 min, EC50 = 27 nM). 1-oleoyl-2-acetylglycerol substituted for PDBu in stimulating the phosphorylation of Mr 80,000 protein (EC50 = 13 microM). Bombesin also caused a striking increase in the phosphorylation of Mr 80,000 protein with a time course similar to that observed with PDBu. This phosphorylation was mimicked by mammalian bombesin-like peptides and blocked by the bombesin antagonists [D-Arg1,D-Phe5,D-Trp7,9,Leu11]
substance P
and [Leu13 psi (CH2NH)Leu14]bombesin. Down-regulation of
protein kinase C
in intact cells by prolonged exposure to PDBu prevented Mr 80,000 protein phosphorylation upon subsequent bombesin addition in digitonin-permeabilized cells. Comigration on one- and two-dimensional gel electrophoresis and phosphopeptide mapping confirmed that the Mr 80,000 protein phosphorylated in permeabilized cells was indistinguishable from the Mr 80,000 protein which is the major protein kinase C substrate in intact cells. The GDP analogue guanosine-5'-O-(2-thiodiphosphate) (GDP beta S) caused a 70% inhibition of the bombesin-induced phosphorylation of Mr 80,000 protein but had no effect on the phosphorylation induced by PDBu. Bombesin stimulated Mr 80,000 protein phosphorylation in permeabilized cells in a dose-dependent manner (EC50 = 4 nM), and GDP beta S shifted the bombesin dose response curve to higher bombesin concentrations (EC50 = 14 nM). These results demonstrate for the first time a growth factor receptor-mediated activation of
protein kinase C
in permeabilized cells and provide functional evidence for the involvement of a G protein in the transmembrane signaling pathway that mediates the stimulation of
protein kinase C
by bombesin in Swiss 3T3 cells.
...
PMID:Bombesin, diacylglycerols, and phorbol esters rapidly stimulate the phosphorylation of an Mr = 80,000 protein kinase C substrate in permeabilized 3T3 cells. Effect of guanine nucleotides. 319 20
Bombesin caused a marked stimulation of 32Pi into phosphatidylinositol (PI), with no apparent lag, and into phosphatidylcholine (PC), after a lag of about 20 min. Stimulation was blocked by the bombesin receptor antagonist, [D-Arg1, D-Pro2, D-Trp7,9, Leu11]
substance P
, indicating that the effects on both PI and PC were mediated through the same receptor. The tumor-promoting phorbol ester 12-0-tetradecanoylphorbol-13-acetate (TPA) and dioctanoylglycerol (diC8) both directly activate
protein kinase C
and in this report were shown to stimulate 32Pi incorporation into PC but not into Pl. In addition, TPA stimulated the release of [3H]choline and [3H]phosphocholine and the accumulation of [3H]diacyglycerol from prelabelled cells. These results strongly suggest that TPA activates a phospholipase C specific for PC. Pretreatment of cells with phorbol-12, 13-dibutyrate (PDBu) for 24 h depleted cellular
protein kinase C
activity and inhibited the ability of TPA to induce these effects suggesting a direct involvement of
protein kinase C
. Similarly the bombesin stimulation of 32Pi into PC and of [3H]choline and [3H]phosphocholine release was inhibited by PDBu pretreatment. DiC8 and, to a lesser extent, TPA stimulated the translocation of CTP:phosphocholine cytidylytransferase from the cytosolic to the particulate fraction. DiC8 also stimulated this translocation in cells depleted of
protein kinase C
. It was concluded that both bombesin and TPA activated
protein kinase C
leading to activation of a phospholipase C specific for PC.
...
PMID:Bombesin and phorbol ester stimulate phosphatidylcholine hydrolysis by phospholipase C: evidence for a role of protein kinase C. 355 93
The distribution of six isoforms of
protein kinase C
(
PKC
) in seromucous acinar cells of rat submandibular gland was examined and their translocation from the cytosolic- to the membrane fraction after different stimuli investigated. Western blotting, immunostaining with isoform-specific antibodies and scanning densitometry showed that PKC-alpha and epsilon were distributed fairly evenly between the cytosol and membranes in resting cells, while isoforms- beta, delta and zeta were all predominantly localized (over 80%) in membranes. PKC-gamma was not detected. PKC-alpha was mobilized to the membrane fraction by the phorbol ester, TPA, but not by the phosphoinositide-coupled agonists carbachol, methoxamine and
substance P
(SP).
PKC
-epsilon was translocated by TPA and carbachol but not by SP or methoxamine. Biochemical assay of total
PKC
confirmed that cytosolic enzyme activity was significantly reduced by TPA and carbachol to 29% and 75% respectively of control levels. These results suggest that muscarinic regulation of the mucosecretory response in the rat submandibular gland may be mediated by the
PKC
-epsilon isoform.
...
PMID:Distribution and translocation of isoforms of protein kinase C in rat submandibular acinar cells. 747 51
1. Somatostatin produces a voltage-dependent inhibition of N-type Ca2+ current in chick sympathetic neurons. Pretreatment of chick sympathetic ganglion neurons with
protein kinase C
(
PKC
) activators has no effect on calcium current (ICa) but reduces the inhibition of ICa by somatostatin. 2. The effects of the alkaloid
PKC
activator (-)-indolactam V were indistinguishable from those of 4 beta-phorbol-12-myristate-13-acetate (4 beta-PMA). The inactive isomers (+)-indolactam V and 4 alpha-PMA did not alter the modulation of ICa by somatostatin. 3. Modulation of ICa by somatostatin desensitizes, with a time for half desensitization of approximately 3 min.
PKC
activation mimics the normal desensitization process in that responses to 30 nM somatostatin are inhibited to a greater extent than are responses to 1 microM somatostatin. 4.
PKC
appears to act at the level of the somatostatin receptor or receptor-G protein interaction because
PKC
activation does not alter Ca2+ current inhibition in response to a nonhydrolyzable analog of GTP, GTP-gamma-S, which directly activates G proteins. 5. The specific
PKC
inhibitor calphostin C largely reverses the effects of phorbol esters, but does not slow the normal rate of desensitization of somatostatin responses. This indicates that
PKC
is not involved in the homologous desensitization of the somatostatin receptor. 6. Neither
substance P
, which activates
PKC
in these cells, nor arachidonic acid, another
PKC
activator, altered the action of somatostatin on ICa.
...
PMID:Protein kinase C blocks somatostatin-induced modulation of calcium current in chick sympathetic neurons. 750 59
New rod photoreceptors are added to mature teleost retinas throughout life by regulated proliferation of rod precursor cells (RPCs). In this study, candidate regulators of RPC proliferation, acidic and basic fibroblast growth factors (aFGF and bFGF; 0.1 microgram/eye), interleukin-6 (IL-6; 0.1 microgram) and phytohaemagglutinin (HA15; 1.0 microgram), were injected intravitreally into one eye of goldfish (body length 5-6 cm), and mitotic RPCs in both retinas were detected and counted 3-50 days later by immunohistochemistry for proliferating cell nuclear antigen (PCNA). Retinal integrity after treatment was assessed by immunohistochemistry for tyrosine hydroxylase (TH) and other retinal antigens. All the agents applied altered the density of PCNA-immunoreactive (ir) cells in the outer and inner nuclear layers (ONL and INL) in both retinas as soon as 2-3 days after unilateral injection. Initially (2-20 days after injection), particularly in the treated retina, PCNA-ir cells appeared in clusters accompanied by various numbers of scattered individual cells, but subsequently the clusters of PCNA-ir cells disappeared while the density of singly distributed cells increased until 30 days after injection. At the doses given, these effects were most striking with aFGF and bFGF and less with IL-6 and HA15. In radial cryosections, other cellular elements immunoreactive to markers such as TH, serotonin, neuropeptide Y,
substance P
, glutamine synthetase, glial fibrillary acidic protein and
protein kinase C
, were found normal in terms of morphology. In addition, a monoclonal antibody (NN-2) was found to label some non-neuronal structures (macrophages, microglia and blood vessels) inside and outside the retina intoxicated with 6-hydroxydopamine, a few NN-2-ir cells being PCNA-positive. However, clustered PCNA-ir and marginal neuroblast cells were NN-2-negative. These results indicate that FGFs may play an important role in stimulating the proliferation of RPCs, for example, in the regeneration of fish retinas following neurotoxic destruction.
...
PMID:Fibroblast growth factor induces proliferating cell nuclear antigen-immunoreactive cells in goldfish retina. 751 Mar 76
The interaction between neurokinin and excitatory amino acid receptors in the spinal cord have been characterised using the neonatal rat spinal cord in vitro preparation. Ventral root (VR) depolarization evoked by N-methyl-D-aspartate (NMDA) and quisqualate was reversibly enhanced in the presence of subthreshold concentrations of
neurokinin A
(NKA; 1.0-10 nM), but not by
substance P
(1.0-5.0 nM). When
substance P
(SP) was replaced by the metabolically stable
substance P
methyl ester (SPOMe), both NMDA and quisqualate responses were significantly enhanced. VR depolarization evoked by kainate was not altered by any of the neurokinin (NK) receptor agonists. In the presence of the endopeptidase inhibitors, bestatin, captopril and thiorphan (each 1.0 microM), SP significantly enhanced NMDA-evoked responses. The selective NK1 receptor antagonist (+/-) CP96 345 (100 nM) reversibly blocked the enhancement of NMDA-evoked depolarization by SPOMe. Furthermore, MEN10 376 (50 nM), a selective NK2 receptor antagonist blocked the enhancement of NMDA- and quisqualate-evoked depolarization by NKA. The
protein kinase C
and protein kinase A inhibitor staurosporine (1.0 microM) blocked the enhancement of excitatory amino acid-induced responses by NK-receptor activation. However, whilst NKA-evoked ventral root depolarization was completely abolished in the presence of staurosporine, SPOMe- and SP-induced depolarizations were unaffected. These data show that activation of NK1 or NK2 receptors enhances NMDA- and quisqualate-evoked ventral root depolarization in the neonatal rat spinal cord. The interaction between neurokinin and excitatory amino acid receptors involves
protein kinase C
activation.
...
PMID:Tachykinin induced regulation of excitatory amino acid responses in the rat spinal cord in vitro. 751 61
The human c-kit receptor ligand, rhSCF, is the only cytokine known to be active on human mast cells, but its intracellular signal transduction pathway is still unknown. We compared the effect of rhSCF on intracellular Ca2+ levels in purified (> 70% pure) adult skin mast cells with two other immunologic stimuli, namely, anti-IgE and
substance P
. Both rhSCF (1 microgram/mL) and anti-IgE (3 micrograms/mL) induced a rapid (< 20 sec) and sustained (T1/2 for decay > 10 min) increase in free cytosolic Ca2+ concentration. In contrast,
substance P
(5 microM) elicited a very rapid (< 1 sec) and transient (T1/2 for decay congruent to 5 sec) rise in intracellular Ca2+ levels. Intracellular cAMP levels were then increased by pharmacologic means to examine the role of the cyclic nucleotide in controlling the Ca2+ response in skin mast cells. A combination of the general phosphodiesterase inhibitor, isobutylmethylxanthine (IBMX) (200 microM) and the adenylate cyclase activator, forskolin (30 microM) was effective in inhibiting the Ca2+ response induced by rhSCF or anti-IgE (82 and 68% inhibition, respectively), while IBMX and forskolin alone were much less effective. The phosphodiesterase isozyme IV inhibitor, rolipram (10 microM), variably affected the increase in Ca2+ levels induced by anti-IgE, but it exerted a significant inhibitory activity on anti-IgE- or rhSCF-induced response in the presence of forskolin (30 micrograms/mL) (33 and 67%, respectively). Two different
protein kinase C
(
PKC
) activators TPA (200 nM) and bryostatin 1 (200 nM) similarly inhibited rhSCF- (22 and 32%, respectively) and anti-IgE-induced (24 and 32%) Ca2+ response. Finally, the kinase inhibitor genistein (30 micrograms/mL) was a somewhat more effective inhibitor of the rise in intracellular Ca2+ induced by rhSCF (100%) than that activated by anti-IgE (54%) (P < 0.05). These data indicate that rhSCF and anti-IgE may act on human mast cells through a common pathway to increase free cytosolic Ca2+ levels and this effect is similarly modulated by various drugs.
...
PMID:Studies of the intracellular Ca2+ levels in human adult skin mast cells activated by the ligand for the human c-kit receptor and anti-IgE. 751 34
Recent evidence suggests that the level of interleukin-6 (IL-6) is elevated in Alzheimer's disease (AD) brains. IL-6 is produced by reactive glial cells and could potentially affect neuronal survival. Understanding the biochemical mechanism that regulates the production and release of IL-6 by astrocytic cells may help to identify potential targets for therapeutic intervention in AD. In the present study, glial fibrillary acidic protein-positive human U373MG astrocytoma cells were used as a model of reactive astrocytes. Production of IL-6 in response to drug treatment was monitored with an ELISA assay. Histamine (1-100 microM),
substance P
(SP; 1-100 nM), and human interleukin-1 beta (IL-1 beta; 1-30 pM) stimulated the release of IL-6 in a time- and concentration-dependent manner, with EC50 values of 4.5 microM, 8 nM, and 4.5 pM, respectively. The respective effects of histamine, SP, and IL-1 beta were effectively blocked by the histamine H1, SP, and IL-1 receptor antagonists, supporting a receptor-mediated event for these agents. Both histamine and SP enhanced the formation of inositol phosphates and increase intracellular calcium levels, suggesting that the phosphatidylinositol bisphosphate/
protein kinase C
pathway may be involved in the IL-6 release process. Indeed, phorbol 12-myristate 13-acetate, a
protein kinase C
activator, also evoked IL-6 release from the U373MG cells. On the other hand, IL-1 beta, which produces a much more robust release of IL-6 than histamine or SP, has no effect on inositol phosphate formation or intracellular calcium levels.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Regulation of the release of interleukin-6 from human astrocytoma cells. 751 68
Human UC11 astrocytoma cells were used to investigate the role of
protein kinase C
(
PKC
) and other kinases in neurokinin (NK)1 receptor desensitization. The selective NK1 receptor agonist [Sar9,Met(O2)11]-
substance P
stimulated a biphasic accumulation of [3H]inositol phosphates ([3H]IPs) in the presence of 10 mM LiCl in cells that had been prelabeled with [3H]inositol. An initial rapid phase of [3H]IP accumulation during the first 1 min was followed by a slower sustained phase for up to 90 min. These results demonstrate that the human NK1 receptor desensitizes rapidly but only partially. The selective
PKC
inhibitor Ro31-8220 did not prevent rapid NK1 receptor desensitization but after a longer incubation significantly potentiated human NK1 receptor agonist-stimulated accumulation of [3H]IPs. These results suggest that, although
PKC
does not mediate the process of rapid desensitization, it does have an inhibitory role at later times. This conclusion is supported by studies with staurosporine, phorbol dibutyrate, and the protein phosphatase inhibitor okadaic acid. Studies using AlF4-, an agent that can directly activate G proteins, and Ro31-8220 suggested that
PKC
can exert inhibitory effects 'downstream' of receptor activation, although immunoprecipitation of the G proteins alpha q/alpha 11 demonstrated that they do not undergo phosphorylation in UC11 cells and are unlikely to be the target of
PKC
-mediated inhibitory feedback. Delayed inhibitory feedback by
PKC
may be mediated by phosphorylation of phospholipase C, although an additional site of action on the NK1 receptor cannot be ruled out.
...
PMID:Protein kinase C mediates delayed inhibitory feedback regulation of human neurokinin type 1 receptor activation of phospholipase C in UC11 astrocytoma cells. 752 12
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