Human vascular smooth muscle responses mediated by α2 mechanisms in vivo and in vitro

1985 ◽  
Vol 68 (s10) ◽  
pp. 147s-150s ◽  
Author(s):  
S. Thom ◽  
J. Calvete ◽  
R. Hayes ◽  
G. Martin ◽  
P. Sever
Keyword(s):  
Smooth Muscle ◽  
Physiological Role ◽  
Smooth Muscle Contraction ◽  
Α1 Receptors ◽  
Dose Dependent ◽  
Higher Doses ◽  
Α2 Receptors ◽  
Autoregulatory Mechanism

1. The effects of compounds with α2-agonist and α2-antagonist properties on human forearm blood flow and on isolated human arterial segments have been studied. 2. The findings from these studies in vivo and in vitro did not provide evidence in support of the hypothesis that postsynaptic α2-receptors mediate smooth muscle contraction in the tissues under investigation. 3. The constriction of the forearm vascular bed in response to low intra-arterial doses of idazoxan (RX 781094), an α2-antagonist, provides evidence for a physiological role for a presynaptic α2 autoregulatory mechanism. 4. The variability of the forearm vascular responses to higher doses of idazoxan highlights the pitfalls that may have misled previous authors in their interpretation of the results of similar studies. A U-shaped dose-response curve to compounds with mixed α2-and α1-antagonist properties may be constructed, which emphasizes the importance of the dose-dependent selectivity of these antagonists at α2- and α1-receptors. 5. The effect of idazoxan on the responses of arterial segments in vitro to exogenous catecholamines was dependent on the integrity of the endothelium, and provides evidence that α2-receptors may mediate release of the endothelium-derived relaxing factor.

Phosphorylation of caldesmon by ERK MAP kinases in smooth muscle

2000 ◽  
Vol 278 (4) ◽  
pp. C718-C726 ◽  
Author(s):  
Jason C. Hedges ◽  
Brian C. Oxhorn ◽  
Michael Carty ◽  
Leonard P. Adam ◽  
Ilia A. Yamboliev ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Map Kinase ◽  
Map Kinases ◽  
Isometric Force ◽  
Phosphorylation Site ◽  
Smooth Muscle Contraction ◽  
Tracheal Smooth Muscle ◽  
Muscarinic Agonists

Phosphorylation of h-caldesmon has been proposed to regulate airway smooth muscle contraction. Both extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinases phosphorylate h-caldesmon in vitro. To determine whether both enzymes phosphorylate caldesmon in vivo, phosphorylation-site-selective antibodies were used to assay phosphorylation of MAP kinase consensus sites. Stimulation of cultured tracheal smooth muscle cells with ACh or platelet-derived growth factor increased caldesmon phosphorylation at Ser789 by about twofold. Inhibiting ERK MAP kinase activation with 50 μM PD-98059 blocked agonist-induced caldesmon phosphorylation completely. Inhibiting p38 MAP kinases with 25 μM SB-203580 had no effect on ACh-induced caldesmon phosphorylation. Carbachol stimulation increased caldesmon phosphorylation at Ser789 in intact tracheal smooth muscle, which was blocked by the M2 antagonist AF-DX 116 (1 μM). AF-DX 116 inhibited carbachol-induced isometric contraction by 15 ± 1.4%, thus dissociating caldesmon phosphorylation from contraction. Activation of M2 receptors leads to activation of ERK MAP kinases and phosphorylation of caldesmon with little or no functional effect on isometric force. P38 MAP kinases are also activated by muscarinic agonists, but they do not phosphorylate caldesmon in vivo.

scholarly journals Decreased airway narrowing and smooth muscle contraction in hyperresponsive pigs

2002 ◽  
Vol 93 (4) ◽  
pp. 1296-1300 ◽  
Author(s):  
Debra J. Turner ◽  
Peter B. Noble ◽  
Matthew P. Lucas ◽  
Howard W. Mitchell
Keyword(s):  
Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Porcine Model ◽  
Smooth Muscle Contraction ◽  
Airway Wall ◽  
Muscle Contractility ◽  
Smooth Muscle Contractility ◽  
Airway Narrowing

Increased smooth muscle contractility or reduced smooth muscle mechanical loads could account for the excessive airway narrowing and hyperresponsiveness seen in asthma. These mechanisms were investigated by using an allergen-induced porcine model of airway hyperresponsiveness. Airway narrowing to electric field stimulation was measured in isolated bronchial segments, over a range of transmural pressures (0–20 cmH2O). Contractile responses to ACh were measured in bronchial segments and in isolated tracheal smooth muscle strips isolated from control and test (ovalbumin sensitized and challenged) pigs. Test airways narrowed less than controls ( P < 0.0001). Test pigs showed reduced contractility to ACh, both in isolated bronchi ( P < 0.01) and smooth muscle strips ( P < 0.01). Thus isolated airways from pigs exhibiting airway hyperresponsiveness in vivo are hyporesponsive in vitro. The decreased narrowing in bronchi from hyperresponsive pigs may be related to decreased smooth muscle contractility. These data suggest that mechanisms external to the airway wall may be important to the hyperresponsive nature of sensitized lungs.

Catecholamine release: mechanism of mercury-induced vascular smooth muscle contraction

1975 ◽  
Vol 229 (1) ◽  
pp. 8-12 ◽  
Author(s):  
HS Solomon ◽  
NK Hollenberg
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Electromagnetic Flowmeter ◽  
Smooth Muscle Contraction ◽  
Release Mechanism ◽  
Adrenergic Blockade ◽  
Mercuric Ion ◽  
Anesthetized Dogs

The mechanism by which mercuric ion (HgCl2) induces contraction of vascular smooth muscle was defined in the kidney of anesthetized dogs and in rabbit aortic strips. In vivo, HgCl2 injected into the renal artery induced a dose-related reduction in renal blood flow (electromagnetic flowmeter) and glomerular filtration rate (creatinine clearance). An intra-arterial infusion of phenoxybenzamine (POB) significantly reduced the vascular response to HgCl2 (P less than 0.001). In vitro, alpha-adrenergic blockade with phentolamine and POB prevented mercury-induced contraction, whereas agents that block serotonin, histamine, acetylcholine, and angiotensin did not do so. Norepinephrine receptor "protection" from phenoxybenzamine blockade sustained the response to HgCl2. Reserpine pretreatment produced a parallel reduction in the response of the aorta to tyramine and mercury. The results are consistent with an indirect action of mercuric ion via release of endogenous catecholamines.

scholarly journals Heme oxygenase metabolites inhibit tubuloglomerular feedback in vivo

2011 ◽  
Vol 300 (4) ◽  
pp. H1320-H1326 ◽  
Author(s):  
Hong Wang ◽  
Jeffrey L. Garvin ◽  
Martin A. D'Ambrosio ◽  
John R. Falck ◽  
Pablo Leung ◽  
...  
Keyword(s):  
Soluble Guanylyl Cyclase ◽  
Inhibitory Effect ◽  
Tubuloglomerular Feedback ◽  
Heme Oxygenases ◽  
Cgmp Signaling ◽  
Laser Capture ◽  
Higher Doses ◽  
Autoregulatory Mechanism

Tubuloglomerular feedback (TGF) is a renal autoregulatory mechanism that constricts the afferent arteriole in response to increases in distal NaCl. Heme oxygenases (HO-1 and HO-2) release carbon monoxide (CO) and biliverdin, which may help control renal function. We showed in vitro that HO products inhibit TGF; however, we do not know whether this also occurs in vivo or the mechanism(s) involved. We hypothesized that in vivo HO-1 and HO-2 in the nephron inhibit TGF via release of CO and biliverdin. We first performed laser capture microdissection followed by real-time PCR and found that both HO-1 and HO-2 are expressed in the macula densa. We next performed micropuncture experiments in vivo on individual rat nephrons, adding different compounds to the perfusate, and found that an HO inhibitor, stannous mesoporphyrin (SnMP), potentiated TGF ( P < 0.05, SnMP vs. control). The CO-releasing molecule (CORM)-3 partially inhibited TGF at 50 μmol/l ( P < 0.01, CORM-3 vs. control) and blocked it completely at higher doses. A soluble guanylyl cyclase (sGC) inhibitor, LY83583, blocked the inhibitory effect of CORM-3 on TGF. Biliverdin also partially inhibited TGF ( P < 0.01, biliverdin vs. control), most likely attributable to decreased superoxide (O2−) because biliverdin was rendered ineffective by tempol, a O2− dismutase mimetic. We concluded that HO-1 and HO-2 in the nephron inhibit TGF by releasing CO and biliverdin. The inhibitory effect of CO on TGF is mediated by the sGC/cGMP signaling pathway, whereas biliverdin probably acts by reducing O2−.

Active and inactive renin in human forearm of hypertensive patients

1991 ◽  
Vol 69 (9) ◽  
pp. 1390-1393 ◽  
Author(s):  
Stefano Taddei ◽  
Stefania Favilla ◽  
Antonio Salvetti
Keyword(s):  
Brachial Artery ◽  
Vascular Tissue ◽  
Physiological Role ◽  
Renin Angiotensin System ◽  
Hypertensive Patients ◽  
Active Renin ◽  
Inactive Renin ◽  
Dose Dependent

Although many in vitro and animal studies indicate the existence of a local renin–angiotensin system, data regarding its physiological role are quite controversial, and moreover, evidence suggesting inactive and active renin release from vascular tissue in vivo is lacking both in animal and humans. The aim of our study was to evaluate whether β-adrenoceptor stimulation, a well-known stimulus to renin production, through isoproterenol might cause local renin production from vessels of the forearm of hypertensive patients. Drugs were infused into the brachial artery at systemically ineffective rates, while forearm blood flow (FBF, venous plethysmography), mean intra-arterial pressure, and heart rate were monitored throughout. Active and inactive vessel renin production was measured by calculating venous-arterial (V-A) differences by simultaneous sampling from brachial artery and an ipsilateral deep vein. Active renin (PRA) and total renin (Sepharose bound trypsin activation) were measured by radioimmunoassay while inactive renin was calculated as the difference between total and active renin. V-A differences were corrected for FBF to calculate renin extraction or production. In a group of 10 patients, isoproterenol, which was infused at increasing cumulative rates (0.03, 0.1, 0.3 μg∙100 mL−1 forearm tissue∙min−1 for 5 min each), caused a dose-dependent increment in FBF that was blunted by intra-arterial propranolol (n = 5) pretreatment (10 μg∙100 mL−1 forearm tissue∙min−1 for 10 min). β-Adrenoceptor stimulation caused a dose-dependent outflow of both active and inactive renin, an effect antagonized by propranolol. In conclusion, our data represent the first evidence in humans of tissue active and inactive renin production in the forearm vascular bed.Key words: tissue renin, active renin, inactive renin, isoproterenol.

Direct association and translocation of PKC-α with calponin

2004 ◽  
Vol 286 (6) ◽  
pp. G954-G963 ◽  
Author(s):  
Suresh B. Patil ◽  
Mercy D. Pawar ◽  
Khalil N. Bitar
Keyword(s):  
Smooth Muscle ◽  
Western Blot ◽  
Smooth Muscle Cells ◽  
Direct Interaction ◽  
Muscle Cells ◽  
Smooth Muscle Contraction ◽  
Direct Association ◽  
Translocated Proteins

Calponin has been implicated in the regulation of smooth muscle contraction through its interaction with F-actin and inhibition of the actin-activated MgATPase activity of phosphorylated myosin. Calponin has also been shown to interact with PKC. We have studied the interaction of calponin with PKC-α and with the low molecular weight heat-shock protein (HSP)27 in contraction of colonic smooth muscle cells. Particulate fractions from isolated smooth muscle cells were immunoprecipitated with antibodies to calponin and Western blot analyzed with antibodies to HSP27 and to PKC-α. Acetylcholine induced a sustained increase in the immunocomplexing of calponin with HSP27 and of calponin with PKC-α in the particulate fraction, indicating an association of the translocated proteins in the membrane. To examine whether the observed interaction in vivo is due to a direct interaction of calponin with PKC-α, a cDNA of 1.3 kb of human calponin gene was PCR amplified. PCR product encoding 622 nt of calponin cDNA (nt 351–972 corresponding to amino acids 92–229) was expressed as fusion glutathione S-transferase (GST) protein in the vector pGEX -KT. We have studied the direct association of GST-calponin fusion protein with recombinant PKC-α in vitro. Western blot analysis of the fractions collected after elution with reduced glutathione buffer (pH 8.0) show a coelution of GST-calponin with PKC-α, indicating a direct association of GST-calponin with PKC-α. These data suggest that there is a direct association of translocated calponin and PKC-α in the membrane and a role for the complex calponin-PKC-α-HSP27, in contraction of colonic smooth muscle cells.

Neutral endopeptidase modulates neurotensin-induced airway contraction

1989 ◽  
Vol 66 (5) ◽  
pp. 2338-2343 ◽  
Author(s):  
T. D. Djokic ◽  
D. J. Dusser ◽  
D. B. Borson ◽  
J. A. Nadel
Keyword(s):  
Smooth Muscle ◽  
Serine Proteases ◽  
Neutral Endopeptidase ◽  
Smooth Muscle Contraction ◽  
Response Curves ◽  
Terminal Fragment ◽  
Carboxypeptidase N

To determine the role of endogenous neutral endopeptidase (NEP) (also called enkephalinase, EC 3.4.24.11) in regulating neurotensin-induced airway contraction, we used phosphoramidon, a specific NEP inhibitor, in the guinea pig. In studies in vitro, neurotensin and the COOH-terminal fragment neurotensin-(8–13) contracted strips of bronchial smooth muscle in a concentration-dependent fashion (P less than 0.001). In contrast, the NH2-terminal fragment neurotensin-(1–11) and the COOH-terminal fragment neurotensin-(12–13), the main fragments of neurotensin hydrolysis by NEP, had no effect. Phosphoramidon (10(-5) M) did not change resting tension but shifted the concentration-response curves to neurotensin to lower concentrations (P less than 0.001), whereas inhibitors of kininase II, aminopeptidases, serine proteases, and carboxypeptidase N were without effect. Removing the epithelium increased the contractile response to neurotensin (P less than 0.001), and phosphoramidon further increased the response to neurotensin in these tissues (P less than 0.001). Similar results were obtained in studies in vivo using aerosolized neurotensin and phosphoramidon. These results suggest that endogenous NEP in the airways modulates the effects of neurotensin on airway smooth muscle contraction by inactivating the peptide.

scholarly journals The Effect of Schinus terebinthifolius Raddi (Anacardiaceae) Bark Extract on Histamine-Induced Paw Edema and Ileum Smooth Muscle Contraction

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Paulo Alexandre Nunes-Neto ◽  
Tadeu José da Silva Peixoto-Sobrinho ◽  
Edilson Dantas da Silva Júnior ◽  
Jamilka Leopoldina da Silva ◽  
Alisson Rodrigo da Silva Oliveira ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Contraction ◽  
Inhibitory Effect ◽  
Experimental Models ◽  
Bark Extract ◽  
Paw Edema ◽  
Guinea Pig Ileum ◽  
Schinus Terebinthifolius

Schinus terebinthifolius Raddi (Anacardiaceae), popularly known as red aroeira, is used in traditional medicine to treat inflammatory, gastric, and respiratory disorders. The aim of this study was to evaluate the antihistaminic activity of S. terebinthifolius (St) bark extract by using in vivo and in vitro experimental models. The effects of St were investigated on contractions induced by histamine, carbachol, and potassium chloride in isolated guinea pig ileum. St was also studied in response to hind paw edema induced by histamine in rats. Experiments revealed that although St (250, 500, and 1,000 µg/mL) reduced the histamine-induced contractions by 9.1±1.8, 50.2±2.0, and 68.9±2.0%, respectively, it did not inhibit contractions induced by carbachol or KCl. The association of St (250 and 500 µg/mL) with hydroxyzine, an H1-antihistamine (0.125 and 0.250 µM), increased the inhibitory effect to 67.0±3.2 and 85.1±2.1%, respectively. Moreover, St (100, 200, and 400 mg/kg) decreased paw edema from its peak by 33.9, 48.4, and 54.8%, respectively, whereas hydroxyzine (70 mg/kg) inhibited the peak edema by 56.5%. Altogether, the results suggest that the bark extract of S. terebinthifolius has an antihistaminic effect (H1).

scholarly journals Potentiating TMEM16A channel function has no effect on airway goblet cells or bronchial and pulmonary vascular smooth muscle function

2020 ◽  
Author(s):  
Henry Danahay ◽  
Roy Fox ◽  
Sarah Lilley ◽  
Holly Charlton ◽  
Kathryn Adley ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Goblet Cell ◽  
Pulmonary Arteries ◽  
Smooth Muscle Contraction ◽  
Cell Numbers ◽  
Channel Function ◽  
Mucin Release

AbstractThe calcium-activated chloride channel TMEM16A enables chloride secretion across several transporting epithelia, including in the airway where it represents a therapeutic target for the treatment of cystic fibrosis. Additional roles for TMEM16A have also been proposed, including enhancing goblet cell exocytosis, increasing goblet cell numbers and stimulating smooth muscle contraction. The aim of the present study was to test whether the pharmacological regulation of TMEM16A channel function, both potentiation and inhibition, could affect any of these proposed biological roles.In vitro, a recently described potent and selective TMEM16A potentiator (ETX001) failed to stimulate mucin release from primary human bronchial epithelial (HBE) cells over a 24h exposure period using both biochemical and imaging endpoints. In addition, treatment of HBE cells with ETX001 or a potent and selective TMEM16A inhibitor (Ani9) for 4 days did not influence mucin release or goblet cell formation. In vivo, a TMEM16A potentiator was without effect on goblet cell emptying in an IL-13 driven goblet cell metaplasia model.Using freshly isolated human bronchi and pulmonary arteries, neither ETX001 or Ani9 had any effect on the contractile or relaxant responses of the tissues. In vivo, ETX001 also failed to influence either lung or cardiovascular function when delivered directly into the airways of telemetered rats.Together, these studies do not support a role for TMEM16A in the regulation of goblet cell numbers or mucin release, or on the regulation of airway or pulmonary artery smooth muscle contraction.

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