Khori V, Naeimipour S, Alizadeh A, Haeri Rouhani A, Pourabouk M, Badaghabadi F, et al . Acute direct effects of cyclosporine on extracellular field potential of isolated rabbit AV node during experimental atrial fibrillation. Physiol Pharmacol 2012; 15 (4) :507-516
URL:
http://ppj.phypha.ir/article-1-741-en.html
Vahid Khori

,
Samaneh Naeimipour

,
Alimohammad Alizadeh

,
Ali Haeri Rouhani

,
Mona Pourabouk

,
Fakhri Badaghabadi

,
Maryam Rajaei

,
Sepideh Shariatnezhad

,
Hamidreza Moheimani

,
Saeed Saleki

,
Mohammad Ali Zeyghami

,
Mohsen Nayebpour
Abstract: (10665 Views)
Introduction: Previous studies have indicated a relationship between MPTP pore and AV nodal rate-dependent
properties. The aim of present study was to determine acute direct effects of cyclosporine on extracellular field potential
of isolated rabbit AV node during experimental atrial fibrillation.
Methods: In one group of male New Zealand rabbits (1.5-2.5 kg) cumulative concentrations of cyclosporine (0.5 –
10 m) were applied on isolated perfused atrio-nodal preparation (n=7). Extracellular field potential recording was
sampled during specific stimulation protocols (recovery, zone of concealment and atrial fibrillation) in the presence of
drug on electrophysiological properties of AV-node.
Results: Cyclosporine significantly decreased the ventricular rate (HH mean) from 231.8 ± 5.7 to 277.4 ± 14.6 msec
and functional refractory period during AF (AF FRP) from 138.3 ± 7.5 to 161.2 ± 10.31 msec in control and treated
groups, respectively. Effective refractory period during AF (AF ERP) was significantly decreased by cyclosporine 10
mM compared to control group (p<0.05).
Conclusion: Cyclosporine-evoked slowing ventricular heart rate during AF was induced by increasing functional
refractoy period and ZOC. A possible mechanism can be through blocking of MPT pores.