A knockout approach indicates a minor vasoconstrictor role for vascular α 1B-adrenoceptors in mouse

2002 ◽  
Vol 9 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Craig J. Daly ◽  
Clare Deighan ◽  
Ann McGee ◽  
Dawson Mennie ◽  
Zeeshan Ali ◽  
...  
Keyword(s):  
Vascular Tone ◽  
Receptor Subtypes ◽  
Wild Type ◽  
Pharmacological Analysis ◽  
Selective Antagonists ◽  
Simplified Analysis ◽  
A Minor ◽  
Isolated Arteries

Pharmacological analysis alone has failed to clarify the role of the three α1-adrenoceptor subtypes in modulating vascular tone, due to a lack of sufficiently selective antagonists, particularly for the α 1B-adrenoceptor, and the complexity when three receptor subtypes are potentially activated by the same agonist. We adopted a combined genetics/ pharmacology strategy based on the α1B-adrenoceptor knockout (KO) mouse. The potency of three α1-adrenoceptor antagonists vs. phenylephrine was tested in aorta, carotid, mesenteric, and caudal isolated arteries from KO and wild-type (WT) mice. In the KO mouse the pharmacology became straightforward, showing α1D in two major conducting arteries (aorta and carotid) and α1A in two distributing arteries (mesenteric and caudal). By combining antagonist pharmacology and genetics, we provide a simplified analysis of α1-mediated vasoconstriction, demonstrating that α1D and α1A are the major subtypes involved in vasoconstriction, with a minor but definite contribution from α1B in every vessel.

scholarly journals Contribution of epoxyeicosatrienoic acids to flow-induced dilation in arteries of male ERα knockout mice: role of aromatase

2007 ◽  
Vol 293 (3) ◽  
pp. R1239-R1246 ◽  
Author(s):  
Dong Sun ◽  
Changdong Yan ◽  
Azita Jacobson ◽  
Houli Jiang ◽  
Mairead A. Carroll ◽  
...  
Keyword(s):  
Gas Chromatography Mass Spectrometry ◽  
Epoxyeicosatrienoic Acids ◽  
Epoxyeicosatrienoic Acid ◽  
Wild Type ◽  
Electrophysiological Technique ◽  
Isolated Arteries ◽  
Oxide Synthase ◽  
Interfering Rna ◽  
Endothelial Nitric Oxide

We studied the roles of estrogen receptors (ER) and aromatase in the mediation of flow-induced dilation (FID) in isolated arteries of male ERα-knockout (ERα-KO) and wild-type (WT) mice. FID was comparable between gracilis arteries of WT and ERα-KO mice. In WT arteries, inhibition of NO and prostaglandins eliminated FID. In ERα-KO arteries, Nω-nitro-l-arginine methyl ester (l-NAME) inhibited FID by ∼26%, whereas indomethacin inhibited dilations by ∼50%. The remaining portion of the dilation was abolished by additional administration of 6-(2-proparglyoxyphenyl)hexanoic acid (PPOH) or iberiotoxin, inhibitors of epoxyeicosatrienoic acid (EET) synthesis and large-conductance potassium channels, respectively. By using an electrophysiological technique, we found that, in the presence of 10 dyne/cm2 shear stress, perfusate passing through donor vessels isolated from gracilis muscle of ERα-KO mice subjected to l-NAME and indomethacin elicited smooth muscle hyperpolarization and a dilator response of endothelium-denuded detector vessels. These responses were prevented by the presence of iberiotoxin in detector or PPOH in donor vessels. Gas chromatography-mass spectrometry (GC-MS) analysis indicated a significant increase in arterial production of EETs in ERα-KO compared with WT mice. Western blot analysis showed a significantly reduced endothelial nitric oxide synthase expression but enhanced expressions of aromatase and ERβ in ERα-KO arteries. Treatment of ERα-KO arteries with specific aromatase short-interfering RNA for 72 h, knocked down the aromatase mRNA and protein associated with elimination of EET-mediation of FID. Thus, FID in male ERα-KO arteries is maintained via an endothelium-derived hyperpolarizing factor/EET-mediated mechanism compensating for reduced NO mediation due, at least in part, to estrogen aromatized from testosterone.

Role of A1 adenosine receptors in regulation of vascular tone

2005 ◽  
Vol 288 (3) ◽  
pp. H1411-H1416 ◽  
Author(s):  
Huda E. Tawfik ◽  
J. Schnermann ◽  
Peter J. Oldenburg ◽  
S. Jamal Mustafa
Keyword(s):  
Adenosine Receptors ◽  
Vascular Tone ◽  
Receptor Subtypes ◽  
Vascular Relaxation ◽  
Response Curves ◽  
Cgs 21680 ◽  
A1 Adenosine Receptors ◽  
The Impact ◽  
Regulation Of Vascular Tone

The vascular response to adenosine and its analogs is mediated by four adenosine receptors (ARs), namely, A1, A2A, A2B, and A3. A2AARs and/or A2BARs are involved in adenosine-mediated vascular relaxation of coronary and aortic beds. However, the role of A1ARs in the regulation of vascular tone is less well substantiated. The aim of this study was to determine the role of A1ARs in adenosine-mediated regulation of vascular tone. A1AR-knockout [A1AR(−/−)] mice and available pharmacological tools were used to elucidate the function of A1ARs and the impact of these receptors on the regulation of vascular tone. Isolated aortic rings from A1AR(−/−) and wild-type [A1AR(+/+)] mice were precontracted with phenylephrine, and concentration-response curves for adenosine and its analogs, 5′- N-ethyl-carboxamidoadenosine (NECA, nonselective), 2-chloro- N6-cyclopentyladenosine (CCPA, A1AR selective), 2-(2-carboxyethyl)phenethyl amino-5′- N-ethylcarboxamido-adenosine (CGS-21680, A2A selective), and 2-chloro- N6-3-iodobenzyladenosine-5′- N-methyluronamide (Cl-IBMECA, A3 selective) were obtained to determine relaxation. Adenosine and NECA (0.1 μM) caused small contractions of 13.9 ± 3.0 and 16.4 ± 6.4%, respectively, and CCPA at 0.1 and 1.0 μM caused contractions of 30.8 ± 4.3 and 28.1 ± 3.9%, respectively, in A1AR(+/+) rings. NECA- and CCPA-induced contractions were eliminated by 100 nM of 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, selective A1AR antagonist). Adenosine, NECA, and CGS-21680 produced an increase in maximal relaxation in A1AR(−/−) compared with A1AR(+/+) rings, whereas Cl-IBMECA did not produce contraction in either A1AR(+/+) or A1AR(−/−) rings. CCPA-induced contraction at 1.0 μM was eliminated by the PLC inhibitor U-73122. These data suggest that activation of A1ARs causes contraction of vascular smooth muscle through PLC pathways and negatively modulates the vascular relaxation mediated by other adenosine receptor subtypes.

Stimulation of renin release by prostaglandin E2 is mediated by EP2 and EP4 receptors in mouse kidneys

2004 ◽  
Vol 287 (3) ◽  
pp. F427-F433 ◽  
Author(s):  
Frank Schweda ◽  
Jürgen Klar ◽  
Shuh Narumiya ◽  
Rolf M. Nüsing ◽  
Armin Kurtz
Keyword(s):  
Vascular Tone ◽  
Threshold Concentration ◽  
Renin Release ◽  
Receptor Subtypes ◽  
Wild Type ◽  
Adrenoceptor Agonist ◽  
Functional Relevance ◽  
Renal Vascular ◽  
Renal Vascular Tone ◽  
Stimulation Of

PGE2 is a potent stimulator of renin release. So far, the contribution of each of the four PGE2 receptor subtypes (EP1–EP4) in the regulation of renin release has not been characterized. Therefore, we investigated the effects PGE2 on renin secretion rates (RSR) from isolated, perfused kidneys of EP1−/−, EP2−/−, EP3−/−, EP4−/−, and wild-type mice. PGE2 concentration dependently stimulated RSR from kidneys of all four knockout strains with a threshold concentration of 1 nM in EP1−/−, EP2−/−, EP3−/−, and wild-type mice, whereas the threshold concentration was shifted to 10 nM in EP4−/− mice. Moreover, the maximum stimulation of RSR by PGE2 at 1 μM was significantly reduced in EP4−/− (12.8-fold of control) and EP2−/− (15.9-fold) compared with wild-type (20.7-fold), EP1−/− (23.8-fold), and EP3−/− (20.1-fold). In contrast, stimulation of RSR by either the loop diuretic bumetanide or the β-adrenoceptor agonist isoproterenol was similar in all strains. PGE2 exerted a dual effect on renal vascular tone, inducing vasodilatation at low concentrations (1 nmol/) and vasoconstriction at higher concentrations (100 nmol/) in kidneys of wild-type mice. In kidneys of EP2−/− as well as EP4−/− mice, vasodilatation at low PGE2 concentrations was prevented, whereas vasoconstriction at higher concentrations was augmented. In contrast, the vasodilatatory component was pronounced in kidneys of EP1 and EP3 knockout mice, whereas in both genotypes the vasoconstriction at higher PGE2 concentrations was markedly blunted. Our data provide evidence that PGE2 stimulates renin release via activation of EP2 and EP4 receptors, whereas EP1 and EP3 receptors appear to be without functional relevance in juxtaglomerular cells. In contrast, all four receptor subtypes are involved in the control of renal vascular tone, EP1 and EP3 receptors increasing, and EP2 as well as EP4 receptors, decreasing it.

scholarly journals Role of M1, M3, and M5 muscarinic acetylcholine receptors in cholinergic dilation of small arteries studied with gene-targeted mice

2011 ◽  
Vol 300 (5) ◽  
pp. H1602-H1608 ◽  
Author(s):  
Adrian Gericke ◽  
Jan J. Sniatecki ◽  
Veronique G. A. Mayer ◽  
Evgeny Goloborodko ◽  
Andreas Patzak ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscarinic Receptor ◽  
Acetylcholine Receptors ◽  
Muscarinic Acetylcholine Receptors ◽  
Receptor Subtypes ◽  
Wild Type ◽  
Luminal Diameter ◽  
Small Arteries ◽  
Muscarinic Acetylcholine

Acetylcholine regulates perfusion of numerous organs via changes in local blood flow involving muscarinic receptor-induced release of vasorelaxing agents from the endothelium. The purpose of the present study was to determine the role of M1, M3, and M5 muscarinic acetylcholine receptors in vasodilation of small arteries using gene-targeted mice deficient in either of the three receptor subtypes (M1R−/−, M3R−/−, or M5R−/− mice, respectively). Muscarinic receptor gene expression was determined in murine cutaneous, skeletal muscle, and renal interlobar arteries using real-time PCR. Moreover, respective arteries from M1R−/−, M3R−/−, M5R−/−, and wild-type mice were isolated, cannulated with micropipettes, and pressurized. Luminal diameter was measured using video microscopy. mRNA for all five muscarinic receptor subtypes was detected in all three vascular preparations from wild-type mice. However, M3 receptor mRNA was found to be most abundant. Acetylcholine produced dose-dependent dilation in all three vascular preparations from M1R−/−, M5R−/−, and wild-type mice. In contrast, cholinergic dilation was virtually abolished in arteries from M3R−/− mice. Deletion of either M1, M3, or M5 receptor genes did not affect responses to nonmuscarinic vasodilators, such as substance P and nitroprusside. These findings provide the first direct evidence that M3 receptors mediate cholinergic vasodilation in cutaneous, skeletal muscle, and renal interlobar arteries. In contrast, neither M1 nor M5 receptors appear to be involved in cholinergic responses of the three vascular preparations tested.

scholarly journals Central-pair microtubular complex of Chlamydomonas flagella: polypeptide composition as revealed by analysis of mutants.

1981 ◽  
Vol 91 (1) ◽  
pp. 69-76 ◽  
Author(s):  
G M Adams ◽  
B Huang ◽  
G Piperno ◽  
D J Luck
Keyword(s):  
Minor Component ◽  
Cellular Growth ◽  
Two Dimensional ◽  
Wild Type ◽  
Beta Tubulin ◽  
Central Pair ◽  
Electrophoresis System ◽  
A Minor ◽  
Dimensional Electrophoresis

Four mutants of Chlamydomonas reinhardtii representing independent gene loci have been shown to lack totally (pf-18, pf-19, and pf-15) or nearly totally (pf-20) the central microtubular pair complex in isolated axonemal preparations. Analysis of 35S-labeled axonemal proteins, using two methods of electrophoresis, reveals that all four mutants lack or are markedly deficient in 18 polypeptides, ranging in molecular weight from 360,000 to 20,000, that are regularly present in wild-type axonemes. Analyses of axonemal proteins labeled by cellular growth on 32P-labeled medium indicates that a subset of 8 of the 18 polypeptides are phosphorylated. Mutant and wild-type axonemes and flagella have been analyzed for their content of tubulin subunits using a high resolution two-dimensional electrophoresis system combined with agarose gel overlays containing either anti-alpha or anti-beta tubulin sera prepared from Chlamydomonas tubulins. The immunoprecipitates identify two major alpha tubulins, a major beta tubulin, and a minor component which is also precipitated by the anti-beta serum. None of these tubulins shows a specific defect in mutant axonemes, nor do the tubulin polypeptides show altered two-dimensional map positions in the mutant flagella. The 18 polypeptides provide a useful signature for identifying other mutants affecting the central-pair microtubular complex. Such mutants could be useful in defining the structural or functional role of these polypeptides in the central microtubules. Efforts to obtain additional central-pair mutants based on the motility phenotype of the four mutants analyzed here have yielded mutants which are allelic to three of the four mutants.

EP2 receptor mediates bronchodilation by PGE2 in mice

2000 ◽  
Vol 88 (6) ◽  
pp. 2214-2218 ◽  
Author(s):  
J. R. Sheller ◽  
Daphne Mitchell ◽  
Barbara Meyrick ◽  
John Oates ◽  
Richard Breyer
Keyword(s):  
Cell Metabolism ◽  
Receptor Activation ◽  
Receptor Subtypes ◽  
Wild Type ◽  
Mechanically Ventilated ◽  
Airway Constriction ◽  
Ep Receptor ◽  
Ep2 Receptor ◽  
Muscle Responses

PGE2 is an important cyclooxygenase product that modulates airway inflammatory and smooth muscle responses. Signal transduction is mediated by four EP receptor subtypes that cause distinct effects on cell metabolism. To determine the role of EP2 receptor activation, we produced a mouse lacking the EP2 receptor by targeted gene disruption. The effect of aerosolized PGE2 and other agonists was measured using barometric plethysmography and by measurements of lung resistance in mechanically ventilated mice. Inhalation of PGE2 inhibited methacholine responses in wild-type but not in mice lacking the EP2 receptor [EP2(−/−)]. After airway constriction was induced by methacholine aerosol, PGE2reduced the airway constriction enhanced pause in wild-type mice (from 0.88 ± 0.15 to 0.55 ± 0.06) but increased it in EP2(−/−) mice (from 0.73 ± 0.08 to 1.27 ± 0.19). Similar results were obtained in mechanically ventilated mice. These data indicate that the EP2 receptor mediates the bronchodilation effect of PGE2.

scholarly journals The Role of Endothelin and Endothelin Receptor Subtypes in Regulation of Fetal Pulmonary Vascular Tone

1994 ◽  
Vol 35 (6) ◽  
pp. 664-670 ◽  
Author(s):  
Jackson Wong ◽  
Jeffrey R Fineman ◽  
Michael A Heymann
Keyword(s):  
Vascular Tone ◽  
Receptor Subtypes ◽  
Endothelin Receptor

Role of endothelins in regulation of vascular tone in the in situ perfused rat adrenals

1998 ◽  
Vol 274 (1) ◽  
pp. E1-E5 ◽  
Author(s):  
Giuseppina Mazzocchi ◽  
Ludwik K. Malendowicz ◽  
Francesco G. Musajo ◽  
Giuseppe Gottardo ◽  
Anna Markowska ◽  
...  
Keyword(s):  
Flow Rate ◽  
Vascular Tone ◽  
Receptor Subtypes ◽  
Left Adrenal Gland ◽  
Kinase C ◽  
Rat Adrenals ◽  
Oxide Synthase ◽  
Regulation Of Vascular Tone

This study examined the role of endothelins (ETs) and their receptor subtypes ETAand ETB in the regulation of vascular tone in the in situ perfused rat left adrenal gland. Endothelin-1 (ET-1), which binds both ETA and ETB receptors, decreased adrenal flow rate of the perfusion medium, and its effect was reversed by the ETA antagonist BQ-123 and enhanced by the ETB antagonist BQ-788. ET-3, which preferentially binds ETB, and the selective ETB agonist BQ-3020 increased adrenal flow rate of perfusate, and their effects were annulled by BQ-788. BQ-123 magnified the effect of ET-3 and did not affect that of BQ-3020. The ETA-mediated decrease and the ETB-mediated rise in the rate of collection of perfusate were abolished by Ro-31–8220, an inhibitor of protein kinase C (PKC), and by N G-nitro-l-arginine methyl ester, an inhibitor of nitric oxide synthase (NOS), respectively. Collectively, these findings suggest that ETs can regulate vascular tone in the in situ perfused rat adrenals via both PKC-coupled ETA and NOS-coupled ETB receptors, the activation of which evokes vasoconstriction and vasodilation, respectively.

Effect of targeted deletions of β1- and β2-adrenergic-receptor subtypes on heart rate variability

2006 ◽  
Vol 290 (1) ◽  
pp. H192-H199 ◽  
Author(s):  
Phillip M. Ecker ◽  
Chu-Chuan Lin ◽  
Jennifer Powers ◽  
Brian K. Kobilka ◽  
Anne M. Dubin ◽  
...  
Keyword(s):  
Heart Rate ◽  
Low Frequency ◽  
Heart Tissue ◽  
Fast Fourier Transformation ◽  
Receptor Subtypes ◽  
Wild Type ◽  
Frequency Domain Methods ◽  
Β2 Adrenergic Receptor ◽  
Β Adrenergic Receptors

β-Adrenergic receptors (β-ARs) play a major role in regulating heart rate (HR) and contractility in the intact cardiovascular system. Three subtypes (β1, β2, and β3) are expressed in heart tissue, and the role of each subtype in regulating cardiac function has previously been determined by using both pharmacological and gene-targeting approaches. However, previous studies have only examined the role of β-ARs in the macrolevel regulation of HR. We employed three knockout (KO) mouse lines, β1-KO, β2-KO, and β1/β2 double KO (DL-KO), to examine the role that β-AR subtypes play in HR variability (HRV) and in the sympathetic and parasympathetic inputs into HR control. Fast Fourier transformation (FFT) in frequency domain methods of ECG spectral analysis was used to resolve HRV into high- and low-frequency (HF and LF) powers. Resting HR (in beats/min) was decreased in β1-KO [488 (SD 27)] and DL-KO [495 (SD 12)] mice compared with wild-type [WT; 638 (SD 30)] or β2-KO [656 (SD 51)] ( P < 0.0005) mice. Mice lacking β1-ARs (β1-KO and DL-KO) had increased HRV (as illustrated by the standard deviation of normal R-R intervals) and increased normalized HF and LF powers compared with mice with intact β1-ARs (WT and β2-KO). These results demonstrate the differential role of β-AR subtypes in regulating autonomic signaling.

scholarly journals Contribution of serotonin receptor subtypes to hallucinogenic activity of 25I-NBOMe and to its effect on neurotransmission

2020 ◽  
Vol 72 (6) ◽  
pp. 1593-1603
Author(s):  
Monika Herian ◽  
Adam Wojtas ◽  
Małgorzata Katarzyna Sobocińska ◽  
Mateusz Skawski ◽  
Alejandro González-Marín ◽  
...  
Keyword(s):  
Frontal Cortex ◽  
Serotonin Receptor ◽  
Glutamate Release ◽  
Local Administration ◽  
Receptor Subtypes ◽  
Microdialysis Probe ◽  
Selective Antagonists ◽  
Freely Moving ◽  
Rat Frontal Cortex

Abstract Background 4-Iodo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (25I-NBOMe) is a potent serotonin (5-HT) receptor agonist with hallucinogenic properties. The aim of our research was to examine the role of the 5-HT2A, 5-HT2C and 5-HT1A serotonin receptor subtypes in 25I-NBOMe hallucinogenic activity and its effect on dopamine (DA), 5-HT and glutamate release in the rat frontal cortex. Methods Hallucinogenic activity was investigated using the wet dog shake (WDS) test. The release of DA, 5-HT and glutamate in the rat frontal cortex was studied using a microdialysis in freely moving rats. Neurotransmitter levels were analyzed by HPLC with electrochemical detection. The selective antagonists of the 5-HT2A, 5-HT2C and 5-HT1A serotonin receptor subtypes: M100907, SB242084 and WAY100635, respectively were applied through a microdialysis probe. Results The WDS response to 25I-NBOMe (1 and 3 mg/kg) was significantly reduced by local administration of M100907 and SB242084 (100 nM). The 25I-NBOMe-induced increase in glutamate, DA and 5-HT release was inhibited by M100907 and SB242084. WAY100635 had no effect on 25I-NBOMe-induced WDS and glutamate release, while it decreased DA and 5-HT release from cortical neuronal terminals. Conclusion The obtained results suggest that 5-HT2A and 5-HT2C receptors play a role in 25I-NBOMe-induced hallucinogenic activity and in glutamate, DA and 5-HT release in the rat frontal cortex as their respective antagonists attenuated the effect of this hallucinogen. The disinhibition of GABA cells by the 5-HT1A receptor antagonist seems to underlie the mechanism of decreased DA and 5-HT release from neuronal terminals in the frontal cortex.

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