title: Differences in the control of basal L-type Ca(2+) current by the cyclic AMP signaling cascade in frog, rat, and human cardiac myocytes.
abstract: β-adrenergic receptors (β-ARs) mediate the positive inotropic effects of catecholamines by cAMP-dependent phosphorylation of the L-type Ca(2+) channels (LTCCs), which provide Ca(2+) for the initiation and regulation of cell contraction. The overall effect of cAMP-modulating agents on cardiac calcium current (I Ca,L) and contraction depends on the basal activity of LTCCs which, in turn, depends on the basal activities of key enzymes involved in the cAMP signaling cascade. Our current work is a comparative study demonstrating the differences in the basal activities of β-ARs, adenylyl cyclase, phosphodiesterases, phosphatases, and LTCCs in the frog and rat ventricular and human atrial myocytes. The main conclusion is that the basal I Ca,L, and consequently the contractile function of the heart, is secured from unnecessary elevation of its activity and energy consumption at the several "checking-points" of cAMP-dependent signaling cascade and the loading of these "checking-points" may vary in different species and tissues.
authors.affiliation: Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania.
authors.forename: Rimantas
authors.initials: R
authors.lastname: Treinys
authors.affiliation: Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania.
authors.forename: Andrius
authors.initials: A
authors.lastname: Bogdelis
authors.affiliation: Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania.
authors.forename: Lina
authors.initials: L
authors.lastname: Rimkutė
authors.affiliation: Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania.
authors.forename: Jonas
authors.initials: J
authors.lastname: Jurevičius
authors.affiliation: Institute of Cardiology, Lithuanian University of Health Sciences, Sukilėlių pr. 17, 50009, Kaunas, Lithuania. arvydas.skeberdis@lsmuni.lt.
authors.forename: Vytenis Arvydas
authors.initials: VA
authors.lastname: Skeberdis
mesh_terms: D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009206:Myocardium / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D011893:Rana esculenta; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D020746:Calcium Channels, L-Type; D011943:Receptors, Adrenergic, beta; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases
keywords: Adenylyl cyclase; Cardiac myocytes; L-type Ca2+ channels; Phosphatase; Phosphodiesterase; Protein kinase A