TTX-sensitive voltage-gated Na+ channels are expressed in mesenteric artery smooth muscle cells

The presence and properties of voltage-gated Na+ channels in mesenteric artery smooth muscle cells (SMCs) were studied using whole cell patch-clamp recording. SMCs from mouse and rat mesenteric arteries were enzymatically dissociated using two dissociation protocols with different enzyme combinations. Na+ and Ca2+ channel currents were present in myocytes isolated with collagenase and elastase. In contrast, Na+ currents were not detected, but Ca2+ currents were present in cells isolated with papain and collagenase. Ca2+ currents were blocked by nifedipine. The Na+ current was insensitive to nifedipine, sensitive to changes in the extracellular Na+ concentration, and blocked by tetrodotoxin with an IC50 at 4.3 nM. The Na+ conductance was half maximally activated at −16 mV, and steady-state inactivation was half-maximal at −53 mV. These values are similar to those reported in various SMC types. In the presence of 1 μM batrachotoxin, the Na+ conductance-voltage relationship was shifted by 27 mV in the hyperpolarizing direction, inactivation was almost completely eliminated, and the deactivation rate was decreased. The present study indicates that TTX-sensitive, voltage-gated Na+ channels are present in SMCs from the rat and mouse mesenteric artery. The presence of these channels in freshly isolated SMC depends critically on the enzymatic dissociation conditions. This could resolve controversy about the presence of Na+ channels in arterial smooth muscle.

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Expression of voltage-dependent K+ channel genes in mesenteric artery smooth muscle cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1999.277.5.g1055 ◽

1999 ◽

Vol 277 (5) ◽

pp. G1055-G1063 ◽

Cited By ~ 32

Author(s):

Chuanli Xu ◽

Yanjie Lu ◽

Guanghua Tang ◽

Rui Wang

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Mesenteric Artery ◽

Muscle Cells ◽

Mesenteric Arteries ◽

Delayed Rectifier ◽

Kv Channel ◽

Channel Proteins ◽

Voltage Dependent ◽

Encoding Genes

Molecular basis of native voltage-dependent K+(Kv) channels in smooth muscle cells (SMCs) from rat mesenteric arteries was investigated. The whole cell patch-clamp study revealed that a 4-aminopyridine-sensitive delayed rectifier K+ current ( I K) was the predominant K+ conductance in these cells. A systematic screening of the expression of 18 Kv channel genes using RT-PCR technique showed that six I K-encoding genes (Kv1.2, Kv1.3, Kv1.5, Kv2.1, Kv2.2, and Kv3.2) were expressed in mesenteric artery. Although no transient outward Kv currents ( I A) were recorded in the studied SMCs, transcripts of multiple I A-encoding genes, including Kv1.4, Kv3.3, Kv3.4, Kv4.1, Kv4.2, and Kv4.3 as well as I A-facilitating Kv β-subunits (Kvβ1, Kvβ2, and Kvβ3), were detected in mesenteric arteries. Western blot analysis demonstrated that four I K-related Kv channel proteins (Kv1.2, Kv1.3, Kv1.5, and Kv2.1) were detected in mesenteric artery tissues. The presence of Kv1.2, Kv1.3, Kv1.5, and Kv2.1 channel proteins in isolated SMCs was further confirmed by immunocytochemistry study. Our results suggest that the native I K in rat mesenteric artery SMCs might be generated by heteromultimerization of Kv genes.

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Ca(2+)-activated and voltage-gated K+ currents in smooth muscle cells isolated from human mesenteric arteries.

The Journal of Physiology ◽

10.1113/jphysiol.1992.sp019386 ◽

1992 ◽

Vol 457 (1) ◽

pp. 431-454 ◽

Cited By ~ 55

Author(s):

S V Smirnov ◽

P I Aaronson

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Muscle Cells ◽

Mesenteric Arteries ◽

Voltage Gated ◽

K Currents

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Hydrogen sulfide-induced relaxation of resistance mesenteric artery beds of rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00331.2004 ◽

2004 ◽

Vol 287 (5) ◽

pp. H2316-H2323 ◽

Cited By ~ 286

Author(s):

Youqin Cheng ◽

Joseph Fomusi Ndisang ◽

Guanghua Tang ◽

Kun Cao ◽

Rui Wang

Keyword(s):

Smooth Muscle ◽

Hydrogen Sulfide ◽

Vascular Smooth Muscle ◽

Smooth Muscle Cells ◽

Vascular Smooth Muscle Cells ◽

Mesenteric Artery ◽

Muscle Cells ◽

Mesenteric Arteries ◽

Vascular Effects ◽

Rat Mesenteric Artery

Hydrogen sulfide (H2S) has been shown recently to function as an important gasotransmitter. The present study investigated the vascular effects of H2S, both exogenously applied and endogenously generated, on resistance mesenteric arteries of rats and the underlying mechanisms. Both H2S and NaHS evoked concentration-dependent relaxation of in vitro perfused rat mesenteric artery beds (MAB). The sensitivity of MAB to H2S (EC50, 25.2 ± 3.6 μM) was about fivefold higher than that of rat aortic tissues. Removal of endothelium or coapplication of charybdotoxin and apamin to endothelium-intact MAB significantly reduced the vasorelaxation effects of H2S. The H2S-induced relaxation of MAB was partially mediated by ATP-sensitive K+ (KATP) channel activity in vascular smooth muscle cells. Pinacidil (EC50, 1.7 ± 0.1 μM, n = 6) mimicked, but glibenclamide (10 μM, n = 6) suppressed, the vasorelaxant effect of H2S. KATP channel currents in isolated mesenteric artery smooth muscle cells were significantly augmented by H2S. l-Cysteine, a substrate of cystathionine-γ-lyase (CSE), at 1 mM increased endogenous H2S production by sixfold in rat mesenteric artery tissues and decreased contractility of MAB. dl-Propargylglycine (a blocker of CSE) at 10 μM abolished l-cysteine-dependent increase in H2S production and relaxation of MAB. Our results demonstrated a tissue-specific relaxant response of resistance arteries to H2S. The stimulation of KATP channels in vascular smooth muscle cells and charybdotoxin/apamin-sensitive K+ channels in vascular endothelium by H2S represents important cellular mechanisms for H2S effect on MAB. Our study also demonstrated that endogenous CSE can generate sufficient H2S from exogenous l-cysteine to cause vasodilation. Future studies are merited to investigate direct contribution of endogenous H2S to regulation of vascular tone.

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Surface Features of Smooth Muscle Cells from the Mesenteric Artery and Vas Deferens

Journal of Cell Science ◽

10.1242/jcs.8.2.427 ◽

1971 ◽

Vol 8 (2) ◽

pp. 427-443 ◽

Cited By ~ 1

Author(s):

C. E. DEVINE ◽

F. O. SIMPSON ◽

W. S. BERTAUD

Keyword(s):

Smooth Muscle ◽

Sarcoplasmic Reticulum ◽

Guinea Pig ◽

Smooth Muscle Cells ◽

Mesenteric Artery ◽

Vas Deferens ◽

Muscle Cells ◽

Mesenteric Arteries ◽

Dense Bodies ◽

Freeze Etching

Smooth muscle cells of small mesenteric arteries and vas deferens of guinea-pig were examined by freeze-etching. The most striking finding was that the surface vesicles lie in roughly longitudinal rows, with areas of membrane free of vesicles in between. The areas free of vesicles are believed to correspond to areas occupied by dense bodies in conventionally fixed and sectioned material. Other cell constituents which could be identified included sarcoplasmic reticulum and, probably, thick myofilaments.

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Abstract 134: Increased Ca2+ Influx Through Cav1.2 in Vascular Smooth Muscle Cells Causes Hypertension Due to Impairment of Acetylcholine-dependent Vascular Relaxation

Circulation Research ◽

10.1161/res.119.suppl_1.134 ◽

2016 ◽

Vol 119 (suppl_1) ◽

Author(s):

xiaoying Zhang ◽

Zhongjian Cheng ◽

Xiaojie Ai ◽

Mingxin Tang ◽

Xiang Hua ◽

...

Keyword(s):

Smooth Muscle ◽

Smooth Muscle Cells ◽

Calcium Channel ◽

Smooth Muscle Cell ◽

Muscle Cell ◽

Mesenteric Artery ◽

Muscle Cells ◽

Mesenteric Arteries ◽

Dependent Manner ◽

Cell Contractility

Calcium channel plays an important role in smooth muscle contraction and relaxation and L-type calcium channel (Cav1.2) antagonist is widely used for treating hypertension. However, whether increasing Ca2+ influx into smooth muscle cells results in hypertension (through increasing smooth muscle cell contractility) or hypotension (through activating BKCa channels) is unclear. Aiming to answer this question, we established a transgenic (TG) mouse model with smooth muscle cell specific (SM22-α promoter driven) overexpression of a splicing variant of Cavβ2 subunit, Cavβ2a, tagged with GFP. Methods and Results: Immunostaining showed that Cavβ2a-GFP expressed in smooth muscle cells specifically and L-type Ca2+ current in smooth muscle cells from the 4 th branch of mesenteric arteries of transgenic mice was significantly increased (5.1±0.7pA/pF in TG, n=12 vs. 2.2±0.5pA/pF in control, n=10). Telemetric blood pressure measurement showed that 24h-averaged systolic pressure was significantly increased (135.2±9.8mmHg, n=25) compared to that of that of control c57bl/6 mice (110.2±7.8mmHg, n=16). The diastolic pressure was also significantly elevated in TG mice than in control mice. Maximum contractility of the 4 th branch mesenteric arteries measured with 40mM KCl was not different between control and TG groups. Sodium nitroprusside relaxed the phenylephrine-precontracted mesenteric artery in the same dose-dependent manner However, acetylcholine induced mesenteric artery relaxation was signficantly impaired in TG mesenteric arteries. Conclusions: Increasing Ca2+ influx through the L-type Ca2+ channel in smooth muscle cells causing hypertension via impairment of acetylcholine-dependent relaxation.

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Upregulation of Na+/Ca2+ exchanger and TRPC6 contributes to abnormal Ca2+ homeostasis in arterial smooth muscle cells from Milan hypertensive rats

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00356.2010 ◽

2010 ◽

Vol 299 (3) ◽

pp. H624-H633 ◽

Cited By ~ 44

Author(s):

Alessandra Zulian ◽

Sergey G. Baryshnikov ◽

Cristina I. Linde ◽

John M. Hamlyn ◽

Patrizia Ferrari ◽

...

Keyword(s):

Blood Pressure ◽

Smooth Muscle ◽

Plasma Membrane ◽

Smooth Muscle Cells ◽

Mesenteric Artery ◽

Transient Receptor Potential ◽

Receptor Potential ◽

Muscle Cells ◽

Mesenteric Arteries ◽

Membrane Microdomains

The Milan hypertensive strain (MHS) of rats is a model for hypertension in humans. Inherited defects in renal function have been well studied in MHS rats, but the mechanisms that underlie the elevated vascular resistance are unclear. Altered Ca2+ signaling plays a key role in the vascular dysfunction associated with arterial hypertension. Here we compared Ca2+ signaling in mesenteric artery smooth muscle cells from MHS rats and its normotensive counterpart (MNS). Systolic blood pressure was higher in MHS than in MNS rats (144 ± 2 vs. 113 ± 1 mmHg, P < 0.05). Resting cytosolic free Ca2+ concentration (measured with fura-2) and ATP-induced Ca2+ transients were augmented in freshly dissociated arterial myocytes from MHS rats. Ba2+ entry activated by the diacylglycerol analog 1-oleoyl-2-acetyl- sn-glycerol (a measure of receptor-operated channel activity) was much greater in MHS than MNS arterial myocytes. This correlated with a threefold upregulation of transient receptor potential canonical 6 (TRPC6) protein. TRPC3, the other component of receptor-operated channels, was marginally, but not significantly, upregulated. The expression of TRPC1/5, components of store-operated channels, was not altered in MHS mesenteric artery smooth muscle. Immunoblots also revealed that the Na+/Ca2+ exchanger-1 (NCX1) was greatly upregulated in MHS mesenteric artery (by ∼13-fold), whereas the expression of plasma membrane Ca2+-ATPase was not altered. Ca2+ entry via the reverse mode of NCX1 evoked by the removal of extracellular Na+ induced a rapid increase in cytosolic free Ca2+ concentration that was significantly larger in MHS arterial myocytes. The expression of α1/α2 Na+ pumps in MHS mesenteric arteries was not changed. Immunocytochemical observations showed that NCX1 and TRPC6 are clustered in plasma membrane microdomains adjacent to the underlying sarcoplasmic reticulum. In summary, MHS arteries exhibit upregulated TRPC6 and NCX1 and augmented Ca2+ signaling. We suggest that the increased Ca2+ signaling contributes to the enhanced vasoconstriction and elevated blood pressure in MHS rats.

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