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Regulation of the L-type Ca2+ channel during cardiomyogenesis: switch from NO to adenylyl cyclase-mediated inhibition

Regulation of the L-type Ca2+ channel during cardiomyogenesis: switch from NO to adenylyl cyclase-mediated inhibition
Regulation of the L-type Ca2+ channel during cardiomyogenesis: switch from NO to adenylyl cyclase-mediated inhibition
In adult mammalian cardiomyocytes, stimulation of muscarinic receptors counterbalances the beta-adrenoceptor-mediated increase in myocardial contractility and heart rate by decreasing the L-type Ca2+ current (ICa) (1, 2). This effect is mediated via inhibition of adenylyl cyclase and subsequent reduction of cAMP-dependent phosphorylation of voltage-dependent L-type Ca2+ channels (3). Little is known, however, about the nature and origin of this pivotal inhibitory pathway. Using embryonic stem cells as an in vitro model of cardiomyogenesis, we found that muscarinic agonists depress ICa by 58 +/-3% (n=34) in early stage cardiomyocytes lacking functional beta-adrenoceptors. The cholinergic inhibition is mediated by the nitric oxide (NO)/cGMP system since it was abolished by application of NOS inhibitors (L-NMA, L-NAME), an inhibitor of the soluble guanylyl cyclase (ODQ), and a selective phosphodiesterase type II antagonist (EHNA). The NO/cGMP-mediated ICa depression was dependent on a reduction of cAMP/protein kinase A (PKA) levels since application of the catalytic subunit of PKA or of the PKA inhibitor PK) prevented the carbachol effect. In late development stage cells, as reported for ventricular cardiomyocytes (2, 4), muscarinic agonists had no effect on basal ICa but antagonized beta-adrenoceptor-stimulated ICa by 43 +/-4% (n=16). This switch in signaling pathways during development is associated with distinct changes in expression of the two NO-producing isoenzymes, eNOS and iNOS, respectively. These findings indicate a fundamental role for NO as a signaling molecule during early embryonic development and demonstrate a switch in the signaling cascades governing ICa regulation.
ES cell-derived cardiomyocytes, patch-clamp, nitric oxide, switch in the regulation of ICa during development
0892-6638
313-324
Ji, G.J.
99c48ef7-5660-4105-8332-98dda889ebae
Fleischmann, B.K.
34493eb9-36d3-4bb0-8126-1365d9e86c05
Bloch, W.
d6624bb0-f7ce-4979-9780-a6290bb2ac8f
Feelisch, M.
8c1b9965-8614-4e85-b2c6-458a2e17eafd
Andressen, C.
65f86c5a-b2ae-4aa1-9912-a58dab14339b
Addicks, K.
4e57ba3a-7a1c-403d-9b37-0fdab7965bf6
Hescheler, J.
b974a26f-9019-43f5-bf03-776f4886224c
Ji, G.J.
99c48ef7-5660-4105-8332-98dda889ebae
Fleischmann, B.K.
34493eb9-36d3-4bb0-8126-1365d9e86c05
Bloch, W.
d6624bb0-f7ce-4979-9780-a6290bb2ac8f
Feelisch, M.
8c1b9965-8614-4e85-b2c6-458a2e17eafd
Andressen, C.
65f86c5a-b2ae-4aa1-9912-a58dab14339b
Addicks, K.
4e57ba3a-7a1c-403d-9b37-0fdab7965bf6
Hescheler, J.
b974a26f-9019-43f5-bf03-776f4886224c

Ji, G.J., Fleischmann, B.K., Bloch, W., Feelisch, M., Andressen, C., Addicks, K. and Hescheler, J. (1999) Regulation of the L-type Ca2+ channel during cardiomyogenesis: switch from NO to adenylyl cyclase-mediated inhibition. The FASEB Journal, 13 (2), 313-324. (PMID:9973319)

Record type: Article

Abstract

In adult mammalian cardiomyocytes, stimulation of muscarinic receptors counterbalances the beta-adrenoceptor-mediated increase in myocardial contractility and heart rate by decreasing the L-type Ca2+ current (ICa) (1, 2). This effect is mediated via inhibition of adenylyl cyclase and subsequent reduction of cAMP-dependent phosphorylation of voltage-dependent L-type Ca2+ channels (3). Little is known, however, about the nature and origin of this pivotal inhibitory pathway. Using embryonic stem cells as an in vitro model of cardiomyogenesis, we found that muscarinic agonists depress ICa by 58 +/-3% (n=34) in early stage cardiomyocytes lacking functional beta-adrenoceptors. The cholinergic inhibition is mediated by the nitric oxide (NO)/cGMP system since it was abolished by application of NOS inhibitors (L-NMA, L-NAME), an inhibitor of the soluble guanylyl cyclase (ODQ), and a selective phosphodiesterase type II antagonist (EHNA). The NO/cGMP-mediated ICa depression was dependent on a reduction of cAMP/protein kinase A (PKA) levels since application of the catalytic subunit of PKA or of the PKA inhibitor PK) prevented the carbachol effect. In late development stage cells, as reported for ventricular cardiomyocytes (2, 4), muscarinic agonists had no effect on basal ICa but antagonized beta-adrenoceptor-stimulated ICa by 43 +/-4% (n=16). This switch in signaling pathways during development is associated with distinct changes in expression of the two NO-producing isoenzymes, eNOS and iNOS, respectively. These findings indicate a fundamental role for NO as a signaling molecule during early embryonic development and demonstrate a switch in the signaling cascades governing ICa regulation.

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More information

Published date: February 1999
Keywords: ES cell-derived cardiomyocytes, patch-clamp, nitric oxide, switch in the regulation of ICa during development
Organisations: Clinical & Experimental Sciences

Identifiers

Local EPrints ID: 337883
URI: http://eprints.soton.ac.uk/id/eprint/337883
ISSN: 0892-6638
PURE UUID: 483c7890-b578-4c03-bc45-6c757dfc7e39
ORCID for M. Feelisch: ORCID iD orcid.org/0000-0003-2320-1158

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Date deposited: 29 Jun 2012 11:27
Last modified: 07 Oct 2020 05:59

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