Electrophysiological effects of agmatine on human atrial fibers

Citation
Xt. Li et al., Electrophysiological effects of agmatine on human atrial fibers, LIFE SCI, 66(24), 2000, pp. 2351-2356
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
LIFE SCIENCES
ISSN journal
0024-3205 → ACNP
Volume
66
Issue
24
Year of publication
2000
Pages
2351 - 2356
Database
ISI
SICI code
0024-3205(20000505)66:24<2351:EEOAOH>2.0.ZU;2-C
Abstract
The objective of the present study was to study the electrophysiological ef fects of agmatine on human atrial fibers obtained at cardiac surgery using standard microelectrode techniques. Agmatine (1 similar to 10 mM) decreased the action potential amplitude (APA), maximum upstroke velocity of phase 0 deplarization (V(ma)x), velocity of diastolic (phase 4) depolarization (VD D), rate of pacemaker firing (RPF), and action potential duration at 50 and 90% of repolarization(APD(50,90)) in a concentration-dependent manner. Pre treatment with N-G-nitro-L-arginine methyl eater (L-NAME, 0.5 mM), a NOS in hibitor, did not affect the electrophysiological effects of agmatine (5 mM) on human atrial fibers. The effects of agmatine (5 mM) could be blocked co mpletely by pretreatment with idazoxan (0.1 mM), an alpha-2 adrenergic rece ptor (alpha(2)-AR) and imidazoline receptor (IR) antagonist. All these resu lts indicate that the effects of agmatine on human atrial fibers are likely due to a decrease of intracellular calcium mediated by IR and/or alpha(2)- AR.