In permanent atrial fibrillation, PDE3 reduces force responses to 5-HT, but PDE3 and PDE4 do not cause the blunting of atrial arrhythmias.

ABSTRACT:

Background and purpose

5-HT increases force and L-type Ca(2) (+) current (ICa,L ) and causes arrhythmias through 5-HT4 receptors in human atrium. In permanent atrial fibrillation (peAF), atrial force responses to 5-HT are blunted, arrhythmias abolished but ICa,L responses only moderately attenuated. We investigated whether, in peAF, this could be due to an increased function of PDE3 and/or PDE4, using the inhibitors cilostamide (300 nM) and rolipram (1 μM) respectively.

Experimental approach

Contractile force, arrhythmic contractions and ICa,L were assessed in right atrial trabeculae and myocytes, obtained from patients with sinus rhythm (SR), paroxysmal atrial fibrillation (pAF) and peAF.

Key results

Maximum force responses to 5-HT were reduced to 15% in peAF, but no

SUBMITTER: Berk E 

PROVIDER: S-EPMC4959958 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature