AIMS: The parasympathetic nervous system is thought to play a key role in atrial fibrillation (AF). Since parasympathetic signalling is primarily mediated by the heterotrimeric G-protein, Galpha(i)betagamma, we hypothesized that targeted inhibition of Galpha(i) interactions in the posterior left atrium (PLA) would modify the substrate for vagal AF. METHODS AND RESULTS: Cell-penetrating(cp)-Galpha(i)1/2 and cp-Galpha(i)3 C-terminal peptides were assessed for their ability to attenuate cholinergic-parasympathetic signalling in isolated feline atrial myocytes and in canine left atrium (LA). Confocal fluorescence microscopy indicated that cp-Galpha(i)1/2 and/or cp-Galpha(i)3 peptides moderated carbachol attenuation of cellular Ca(2+) transients in isolated atrial myocytes. High-density epicardial mapping of dog PLA, left atrial pulmonary veins (PVs), and left atrial appendage (LAA) indicated that the delivery of cp-Galpha(i)1/2 peptide or cp-Galpha(i)3 peptide into the PLA prolonged effective refractory periods at baseline and during vagal stimulation in the PLA and to varying extents also in the LAA and PV regions. After delivery of cp-Galpha(i) peptides into the PLA, AF inducibility during vagal stimulation was significantly diminished. CONCLUSION: These results demonstrate the feasibility of using specific G(i)-protein inhibition to achieve selective parasympathetic denervation in the PLA, with a resulting change in vagal responsiveness across the entire LA.
AIMS: The parasympathetic nervous system is thought to play a key role in atrial fibrillation (AF). Since parasympathetic signalling is primarily mediated by the heterotrimeric G-protein, Galpha(i)betagamma, we hypothesized that targeted inhibition of Galpha(i) interactions in the posterior left atrium (PLA) would modify the substrate for vagal AF. METHODS AND RESULTS: Cell-penetrating(cp)-Galpha(i)1/2 and cp-Galpha(i)3 C-terminal peptides were assessed for their ability to attenuate cholinergic-parasympathetic signalling in isolated feline atrial myocytes and in canine left atrium (LA). Confocal fluorescence microscopy indicated that cp-Galpha(i)1/2 and/or cp-Galpha(i)3 peptides moderated carbachol attenuation of cellular Ca(2+) transients in isolated atrial myocytes. High-density epicardial mapping of dog PLA, left atrial pulmonary veins (PVs), and left atrial appendage (LAA) indicated that the delivery of cp-Galpha(i)1/2 peptide or cp-Galpha(i)3 peptide into the PLA prolonged effective refractory periods at baseline and during vagal stimulation in the PLA and to varying extents also in the LAA and PV regions. After delivery of cp-Galpha(i) peptides into the PLA, AF inducibility during vagal stimulation was significantly diminished. CONCLUSION: These results demonstrate the feasibility of using specific G(i)-protein inhibition to achieve selective parasympathetic denervation in the PLA, with a resulting change in vagal responsiveness across the entire LA.
Authors: Janna E Slessareva; Hongzheng Ma; Karyn M Depree; Lori A Flood; Hyunsu Bae; Theresa M Cabrera-Vera; Heidi E Hamm; Stephen G Graber Journal: J Biol Chem Date: 2003-10-02 Impact factor: 5.157
Authors: Jason Ng; Roger Villuendas; Ivan Cokic; Jorge E Schliamser; David Gordon; Hemanth Koduri; Brandon Benefield; Julia Simon; S N Prasanna Murthy; Jon W Lomasney; J Andrew Wasserstrom; Jeffrey J Goldberger; Gary L Aistrup; Rishi Arora Journal: Circ Arrhythm Electrophysiol Date: 2011-03-18
Authors: Gary L Aistrup; Ivan Cokic; Jason Ng; David Gordon; Hemanth Koduri; Suzanne Browne; Dorina Arapi; Yogita Segon; Jacob Goldstein; Abigail Angulo; J Andrew Wasserstrom; Jeffrey J Goldberger; Alan H Kadish; Rishi Arora Journal: Heart Rhythm Date: 2011-08-25 Impact factor: 6.343