Demonstration of functional M<sub>3</sub>‐muscarinic receptors in ventricular cardiomyocytes of adult rats

Pönicke, Klaus; Heinroth-Hoffmann, Ingrid; Brodde, Otto‐Erich

doi:10.1038/sj.bjp.0704997

Cited by 49 publications

(34 citation statements)

References 19 publications

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“…After activation of cardiac M 2 receptor in atrium, the ␤␥ subunit of the G i protein directly activates the inwardly rectifying muscarinic K ϩ channel, i.e., the ACh receptor-operated K ϩ channel (Yamada et al, 1998). Although the M 2 receptor is a predominant muscarinic receptor subtype presented in heart, the presence of low levels of non-M 2 muscarinic receptors including M 3 receptor subtype was reported (Pönicke et al, 2003;Wang et al, 2004;Myslivecek et al, 2008). Muscarinic M 3 -receptor blockade by 4-DAMP almost completely abolished the positive response to CCh with slight inhibition of the negative response in the present study.…”

Section: Discussionsupporting

confidence: 42%

Involvement of Cyclooxygenase-2 in Carbachol-Induced Positive Inotropic Response in Mouse Isolated Left Atrium

Hara

Ike²,

Tanida³

et al. 2009

J Pharmacol Exp Ther

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The mouse heart is expected to have characteristic contractile properties. However, basic information on the function of the mouse heart has not been accumulated sufficiently. In this study, the involvement of cyclooxygenase (COX)-2 in carbachol (CCh)-induced inotropic response was investigated in mouse isolated left atrium. Influences of CCh and their mechanisms of action on developed tension elicited by electrical stimulation were examined pharmacologically. The presence of COX-2 in atrium was examined by Western blotting and immunohistochemical analysis. CCh (3 M for 15 min) produced a biphasic inotropic response: a transient decrease in contractile force followed by a late increase. Atropine suppressed the biphasic inotropic response to CCh. A muscarinic M 3 receptor antagonist, 4-diphenyl-acetoxy-N-methlpiperidine, inhibited the late positive inotropic action. Blockade of prostaglandin (PG) E 2 or F 2␣ receptor by 6-isopropoxy-9-oxoxanthene-2-carboxylic acid (AH6809) or 9␣, 15R-dihydroxy-11␤-fluoro-15-(2,3-dihydro-1H-inden-2-yl)-16,17,18,19,20-pentanor-prosta 5Z, 13E-dien-1-oic acid (AL8810), respectively, significantly suppressed the positive inotropic response to CCh. A nonselective COX inhibitor, indomethacin, and a selective COX-2 inhibitor, N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide (NS-398) inhibited the positive response. A COX-1 inhibitor, valeroyl salicylate, did not affect the positive response. The positive response was almost completely abolished in the endocardial endothelium-deprived atria. Existence of COX-2 in endocardial endothelium was confirmed by Western blotting and immunohistochemical analysis. The present study indicated that the CCh-induced positive inotropic response was mediated by PGs, possibly PGE 2 and PGF 2␣ , released in part from endocardial endothelium. Furthermore, for the first time, we demonstrated that the production of PGs depended in part on COX-2 in endocardial endothelium through the muscarinic M 3 receptor stimulation.

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Section: Discussionsupporting

confidence: 42%

Involvement of Cyclooxygenase-2 in Carbachol-Induced Positive Inotropic Response in Mouse Isolated Left Atrium

Hara

Ike²,

Tanida³

et al. 2009

J Pharmacol Exp Ther

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“…An immunohistochemical study indicated that M 3 receptors are present on cardiomyocytes (Wang et al, 2001). In addition, M 3 receptor-mediated increases in inositol phosphate formation have been observed with dispersed cardiomyocytes (Pönicke et al, 2003;Myslivecek et al, 2008). Alternatively, because M 3 receptor-mediated positive inotropic effects were abolished by treatment with 1% Triton X-100 or indomethacin, it has been proposed that M 3 receptors present on the endocardial endothelium stimulate the production of endogenous prostaglandins eliciting positive inotropic actions (Tanaka et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…However, the M 2 receptor is not the only muscarinic receptor subtype present in the heart (Wang et al, 2004). Pharmacological, biochemical, immunohistochemical, and molecular biological studies using whole heart tissues or isolated cardiomyocytes indicate that the heart, es-pecially cardiomyocytes, also expresses low levels of non-M 2 muscarinic receptors, including the M 1 and M 3 receptor subtypes (Gallo et al, 1993;Sharma et al, 1996;Hardouin et al, 1998;Hellgren et al, 2000;Wang et al, 2001Wang et al, , 2004Krejcí and Tucek, 2002;Pönicke et al, 2003;Willmy-Matthes et al, 2003;Pérez et al, 2006;Myslivecek et al, 2008).…”

mentioning

confidence: 99%

M₃ Muscarinic Receptors Mediate Positive Inotropic Responses in Mouse Atria: A Study with Muscarinic Receptor Knockout Mice

Kitazawa¹,

Asakawa²,

Nakamura³

et al. 2009

J Pharmacol Exp Ther

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The potential functional roles of M 3 muscarinic receptors in mouse atria were examined by pharmacological and molecular biological techniques, using wild-type mice, muscarinic M 2 or M 3 receptor single knockout (M 2 KO, M 3 KO), and M 2 and M 3 muscarinic receptor double knockout mice (M 2 /M 3 KO). Realtime quantitative reverse transcriptase-polymerase chain reaction analysis showed that the M 2 receptor mRNA was expressed predominantly in mouse atria but that the M 1 , M 3 , M 4 , and M 5 receptor subtypes were also expressed at low levels. Carbachol (10 nM-30 M) decreased the spontaneous beating frequency of right atria isolated from wild-type mice. Studies with subtype-preferring antagonists and atria from M 2 KO mice confirmed that this activity is mediated by the M 2 receptor subtype. In left atria from wild-type mice, carbachol decreased the amplitude of electrical field stimulation-evoked contractions (negative inotropic action), but this inhibition was transient and was followed by a gradual increase in contraction amplitude (positive inotropic response). In atria from M 3 KO mice, the transient negative inotropic action of carbachol changed to a sustained negative inotropic action. In contrast, in atria from M 2 KO mice, carbachol showed only positive inotropic activity. In atria from M 2 /M 3 double KO mice, carbachol was devoid of any inotropic activity. These observations, complemented by functional studies with subtype-preferring antagonists, convincingly demonstrate that atrial M 3 muscarinic receptors mediate positive inotropic effects in mouse atria. Physiologically, this activity may serve to dampen the inhibitory effects of M 2 receptor activation on atrial contractility.Muscarinic receptor stimulation by acetylcholine plays an important role in parasympathetic control of cardiac functions such as heart rate (chronotropic action), conduction velocity (dromotropic action), and contractility (inotropic action). Muscarinic receptors are prototypic members of the superfamily of G protein-coupled receptors, and molecular cloning studies have demonstrated the existence of five distinct mammalian muscarinic receptor subtypes (M 1 -M 5 ) (Caulfield and Birdsall, 1998). Based on their differential G protein-coupling properties, the five receptors can be subdivided into two major functional classes. The M 1 , M 3 , and M 5 receptors preferentially couple to G q/11 proteins, whereas the M 2 and M 4 receptors are selectively linked to G i/o proteins (Caulfield and Birdsall, 1998;Lanzafame et al., 2003). It is well documented that the heart predominantly expresses the M 2 receptor subtype (Brodde and Michel, 1999;Dhein et al., 2001). After activation of cardiac M 2 receptors, the activated ␣ subunit of G i proteins inhibits adenylate cyclase activity, resulting in a decrease of cytoplasmic cAMP, whereas the ␤␥ subunit of the G i proteins directly activates the inwardly rectifying muscarinic K ϩ channel (Yamada et al., 1998;Dhein et al., 2001). However, the M 2 receptor is not the only muscarinic ...

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“…These effects are particularly strong in pacemaker and atrial tissues. The M 2 muscarinic receptors prevail in the mammalian myocardium, although some M 3 receptors are also present and physiologically active (Pönicke et al, 2003;Wang et al, 2007). The even-numbered muscarinic receptors, including M 2 , are coupled to G i proteins and act via inhibition of adenylate cyclase and a subsequent decrease in cellular cAMP content (Dhein et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

A new potassium ion current induced by stimulation of M2-cholinoreceptors in fish atrial myocytes

Abramochkin

Tapilina

Vornanen

2014

Journal of Experimental Biology

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A novel potassium ion current induced by muscarinic stimulation (IKACh2) is characterized in atrial cardiomyocytes of teleost fishes (crucian carp, Carassius carassius L.; rainbow trout, Oncorhynchus mykiss W.) by means of the whole-cell patch-clamp technique. The current is elicited in atrial, but not ventricular, cells by application of carbamylcholine (CCh) in moderate and high concentrations (10-7 - 10-4 M). It can be distinguished from the classic IKACh, activated by βγ-subunit of the Gi-protein, due to its low sensitivity to Ba2+ ions and distinct current-voltage relationship with a very small inward current component. Ni2+ ions (5 mM) and KB-R7943 (10-5 M), non-selective blockers of the sodium-calcium exchange current (INCX), strongly reduced and completely abolished, respectively, the IKACh2. Therefore, IKACh2 was initially regarded as a CCh-induced outward component of the INCX. However, the current is not affected by either exclusion of intracellular Na+ or extracellular Ca2+, but is completely abolished by intracellular perfusion with K-+ free solution. Atropine (10-6 M), a non-selective muscarinic blocker, completely eliminated the IKACh2. A selective antagonist of M2 cholinoreceptors, AF-DX 116 (2×10-7M) and a M3 antagonist, 4-DAMP (10-9M), decreased IKACh2 by 84.4% and 16.6% respectively. Pertussis toxin, which irreversibly inhibits Gi-protein coupled to M2 receptors, reduced the current by 95%, when applied into the pipette solution. It is concluded that IKACh2, induced by stimulation of M2 cholinoceptors and subsequent Gi-protein activation represents a new molecular target for the cardiac parasympathetic innervation.

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Demonstration of functional M₃‐muscarinic receptors in ventricular cardiomyocytes of adult rats

Cited by 49 publications

References 19 publications

Involvement of Cyclooxygenase-2 in Carbachol-Induced Positive Inotropic Response in Mouse Isolated Left Atrium

Involvement of Cyclooxygenase-2 in Carbachol-Induced Positive Inotropic Response in Mouse Isolated Left Atrium

M₃ Muscarinic Receptors Mediate Positive Inotropic Responses in Mouse Atria: A Study with Muscarinic Receptor Knockout Mice

A new potassium ion current induced by stimulation of M2-cholinoreceptors in fish atrial myocytes

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Demonstration of functional M3‐muscarinic receptors in ventricular cardiomyocytes of adult rats

Cited by 49 publications

References 19 publications

Involvement of Cyclooxygenase-2 in Carbachol-Induced Positive Inotropic Response in Mouse Isolated Left Atrium

Involvement of Cyclooxygenase-2 in Carbachol-Induced Positive Inotropic Response in Mouse Isolated Left Atrium

M3 Muscarinic Receptors Mediate Positive Inotropic Responses in Mouse Atria: A Study with Muscarinic Receptor Knockout Mice

A new potassium ion current induced by stimulation of M2-cholinoreceptors in fish atrial myocytes

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Demonstration of functional M₃‐muscarinic receptors in ventricular cardiomyocytes of adult rats

M₃ Muscarinic Receptors Mediate Positive Inotropic Responses in Mouse Atria: A Study with Muscarinic Receptor Knockout Mice