Dexamethasone decreases neuronal nitric oxide release in mesenteric arteries from hypertensive rats through decreased protein kinase C activation

2009 ◽  
Vol 117 (8) ◽  
pp. 305-312 ◽  
Author(s):  
Rosa Aras-López ◽  
Fabiano E. Xavier ◽  
Mercedes Ferrer ◽  
Gloria Balfagón
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Glucocorticoid Receptors ◽  
Electrical Field Stimulation ◽  
Mesenteric Arteries ◽  
Hypertensive Rats ◽  
Pkc Inhibitor ◽  
Kinase C ◽  
No Release ◽  
Wistar Kyoto

Neuronal NO plays a functional role in many vascular tissues, including MAs (mesenteric arteries). Glucocorticoids alter NO release from endothelium and the CNS (central nervous system), but no results from peripheral innervation have been reported. In the present study we investigated the effects of dexamethasone on EFS (electrical field stimulation)-induced NO release in MAs from WKY (Wistar–Kyoto) rats and SHRs (spontaneously hypertensive rats) and the role of PKC (protein kinase C) in this response. In endothelium-denuded MAs, L-NAME (NG-nitro-L-arginine methyl ester) increased the contractile response to EFS only in segments from SHRs. EFS-induced contraction was reduced by 1 μmol/l dexamethasone in segments from SHRs, but not WKY rats, and this effect was abolished in the presence of dexamethasone. EFS induced a tetrodotoxin-resistant NO release in WKY rat MAs, which remained unchanged by 1 μmol/l dexamethasone. In SHR MAs, dexamethasone decreased basal and EFS-induced neuronal NO release, and this decrease was prevented by the glucocorticoid receptor antagonist mifepristone. Dexamethasone did not affect nNOS [neuronal NOS (NO synthase)] expression in either strain. In SHR MAs, incubation with calphostin C (a non-selective PKC inhibitor), Gö6983 (a classic PKC δ and ζ inhibitor), LY379196 (a PKCβ inhibitor) or PKCζ-PI (PKCζ pseudosubstrate inhibitor) decreased both basal and EFS-induced neuronal NO release. Additionally, PKC activity was reduced by dexamethasone. The PKC inhibitor-induced reduction in NO release was unaffected by dexamethasone. In conclusion, results obtained in the present study indicate that PKC activity positively modulates the neuronal NO release in MAs from SHRs. They also reveal that by PKC inhibition, through activation of glucocorticoid receptors, dexamethasone reduces neuronal NO release in these arteries.

Role of protein kinase C in electrical-stimulation-induced neuronal nitric oxide release in mesenteric arteries from hypertensive rats

2000 ◽  
Vol 99 (4) ◽  
pp. 277-283 ◽  
Author(s):  
Jesús MARÍN ◽  
Mercedes FERRER ◽  
Gloria BALFAGÓN
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
No Synthase ◽  
Mesenteric Arteries ◽  
Protein Synthesis Inhibitor ◽  
Hypertensive Rats ◽  
Wky Rats ◽  
Kinase C ◽  
No Release

This study examines the influence of hypertension on neuronal nitric oxide (NO) release and its modulation by protein kinase C (PKC). For this purpose, mesenteric segments without endothelium were obtained from Wistar–Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs), and neurogenic NO release induced by electrical field stimulation (EFS) was examined in these segments. EFS induced frequency-dependent contractions. The NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) and the sensorial neurotoxin capsaicin increased EFS-induced contractions in SHR segments, but did not affect these contractions in segments from WKY rats. In segments from SHRs, the increase in EFS-induced response by capsaicin was further increased by the combination of capsaicin and L-NAME. EFS-induced contractions in SHR arteries were unaltered by the protein synthesis inhibitor cycloheximide or by 2-amine-5,6-dihydro-6-methyl-4H-1,3-tiazine (AMT), an inhibitor of inducible NO synthase, and increased by the guanylate cyclase inhibitor Methylene Blue. In these arteries, capsaicin plus the PKC inhibitor calphostin C increased the contractions elicited by EFS; the addition of L-NAME did not affect this increase. Phorbol 12,13-dibutyrate (PDBu) did not modify the response to EFS in these arteries pretreated with capsaicin, although a combination of PDBu and L-NAME was effective. These results indicate that, in mesenteric arteries, EFS induces the release of NO from perivascular nitrergic nerves and of neuropeptides from sensory nerves, but only in hypertensive rats. The NO released is synthesized by constitutive neuronal NO synthase in a manner that is positively modulated by PKC, an enzyme that seems to be activated in hypertension.

Mitogenic Events Induced by Vasopressin in Aortic Fibroblasts from Spontaneously Hypertensive Rats

1993 ◽  
Vol 85 (1) ◽  
pp. 57-61 ◽  
Author(s):  
Ding Liang Zhu ◽  
Thierry Herembert ◽  
Pierre Marche
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Arginine Vasopressin ◽  
Spontaneously Hypertensive Rats ◽  
Thymidine Incorporation ◽  
Inositol Phosphate ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Kinase C ◽  
Wistar Kyoto

1. To further explore the mechanisms of arterial growth, we investigated the signalling pathways through which arginine-vasopressin acts as a mitogen in cultured adventitial aortic fibroblasts of the spontaneously hypertensive rat, and we examined the mechanisms involved in the hyperresponsiveness to arginine-vasopressin of fibroblasts from spontaneously hypertensive rats compared with fibroblasts from Wistar-Kyoto rats. 2. Arginine-vasopressin-induced [3H]thymidine incorporation was used to determine the peptide mitogenicity. Arginine-vasopressin-triggered hydrolysis of phosphoinositides by phospholipase C was evaluated by measuring [3H]inositol phosphate formation. The role of protein kinase C and protein tyrosine kinases in arginine-vasopressin mitogenicity was assessed by stimulating the cells with arginine-vasopressin in the presence of 12-O-tetradecanoylphorbol 13-acetate and tyrphostin (a tyrosine kinase inhibitor), respectively. 3. Arginine-vasopressin-induced DNA synthesis was completely abolished in confluent cells, whereas [3H]inositol phosphate formation was only reduced. The presence of 12-O-tetradecanoylphorbol 13-acetate markedly decreased arginine-vasopressin-induced [3H]thymidine incorporation in fibroblasts from spontaneously hypertensive rats and was without effect in fibroblasts from Wistar-Kyoto rats. Tyrphostin abolished arginine-vasopressin-induced [3H]thymidine incorporation in a dose-dependent manner and did not affect the formation of inositol phosphates. 4. These results indicate that phospholipase C activation is not sufficient for arginine-vasopressin-induced mitogenesis. They also suggest that (i) tyrosine kinase activation is a necessary step in the transduction of the arginine-vasopressin mitogenic signal, and (ii) protein kinase C participates in the increased mitogenic potency of arginine-vasopressin in spontaneously hypertensive rats.

scholarly journals Protein kinase C activation increases endothelial nitric oxide release in mesenteric arteries from orchidectomized rats

2007 ◽  
Vol 192 (1) ◽  
pp. 189-197 ◽  
Author(s):  
Javier Blanco-Rivero ◽  
Ana Sagredo ◽  
Gloria Balfagón ◽  
Mercedes Ferrer
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase C ◽  
Mesenteric Arteries ◽  
Enos Expression ◽  
Pkc Inhibitor ◽  
Calphostin C ◽  
Kinase C ◽  
No Release ◽  
Male Sex ◽  
Endothelial Nitric Oxide

The aim of the present study was to assess the effect of endogenous male sex hormones on endothelial nitric oxide synthase (eNOS) expression, release and function of the endothelial nitric oxide (NO), as well as to assess the regulatory action of protein kinase C (PKC) on acetylcholine (ACh)-induced endothelial NO release. For this purpose, superior mesenteric arteries from control and orchidectomized male Sprague–Dawley rats were used. eNOS expression and basal-and ACh-induced NO release were similar in arteries from both groups of rats. Orchidectomy decreased the vasodilator effect induced by ACh but did not alter that induced by sodium nitroprusside (SNP). The superoxide anion scavenger, superoxide dismutase (SOD), or the membrane-permeable mimetic of SOD, tempol, only enhanced ACh-induced relaxation in arteries from orchidectomized rats. ACh-induced TXA2 formation was higher in arteries from orchidectomized than from control rats. Neither the PKC activator, phorbol 12,13-dibutyrate (PDBu), nor the non-selective PKC inhibitor, calphostin C, modified basal- or ACh-induced NO release in arteries from control rats. In arteries from orchidectomized rats, basal- and ACh-induced endothelial NO release were increased by PDBu but decreased by calphostin C. Both Gö6976, a PKC inhibitor that is partially selective for conventional PKC isoforms, as well as PKCζ pseudosubstrate inhibitor (PKCζ-PI) decreased both basal- and ACh-induced NO release in arteries from orchidectomized rats. Neither PDBu nor calphostin C modified the vasodilator response induced by ACh in arteries from control rats. In segments from orchidectomized rats, PDBu enhanced the ACh-induced response, but this response was not modified by calphostin C, Gö6976 or PKCζ-PI. The vasodilator response induced by SNP was not altered by the PKC activators or inhibitors in any artery from either group. These results show that endogenous male sex hormone deprivation does not affect the eNOS expression or the endothelial NO release induced by ACh, but does decrease the vasodilator action of ACh, by increasing NO metabolism and TXA2 formation. In addition, PKC seems to modulate eNOS activity only in mesenteric arteries from orchidectomized rats, in which conventional and PKCζ isoforms are involved in the positive regulation of eNOS.

Altered Cardiac Endothelin Receptors and Protein Kinase C in Deoxycorticosterone-Salt Hypertensive Rats

2000 ◽  
Vol 32 (4) ◽  
pp. 665-676 ◽  
Author(s):  
Jeannette Fareh ◽  
Rhian M Touyz ◽  
Ernesto L Schiffrin ◽  
Gaétan Thibault
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Endothelin Receptors ◽  
Hypertensive Rats ◽  
Kinase C

Expression of myogenic constrictor tone in the aorta of hypertensive rats

2001 ◽  
Vol 280 (4) ◽  
pp. R968-R975 ◽  
Author(s):  
Michelle Rapacon-Baker ◽  
Fan Zhang ◽  
Michael L. Pucci ◽  
Hui Guan ◽  
Alberto Nasjletti
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Calcium Channels ◽  
Thoracic Aorta ◽  
Calcium Influx ◽  
Intraluminal Pressure ◽  
Hypertensive Rats ◽  
Calcium Dependent ◽  
Kinase C ◽  
Basal Tone

We investigated the effect of intraluminal pressure or stretch on the development of tone in the descending thoracic aorta from rats with aortic coarctation-induced hypertension of 7–14 days duration. Increments of pressure >100 mmHg decreased the diameter of thoracic aortas from hypertensive but not from normotensive rats. The pressure-induced constriction was not demonstrable in vessels superfused with calcium-free buffer. Stretched rings of aorta from hypertensive rats exhibited a calcium-dependent constrictor tone accompanied by elevated calcium influx that varied in relation to the degree of stretch. Blockers of l-type calcium channels and inhibitors of protein kinase C reduced both basal tone and calcium influx in aortic rings of hypertensive rats. Hence, the thoracic aorta of hypertensive rats expresses a pressure- and stretch-activated constrictor mechanism that relies on increased calcium influx throughl-type calcium channels via a protein kinase C-regulated pathway. The expression of such a constrictor mechanism is suggestive of acquired myogenic behavior.

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