Volume 15, Issue 2 (Summer 2011)                   Physiol Pharmacol 2011, 15(2): 173-181 | Back to browse issues page

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Khori V, Alizadeh A, Niknam M, Moheimani H R, Yazdi H, Pourabouk M, et al . Dynamic age-related changes of extracellular field potential of isolated AV-node of rabbit. Physiol Pharmacol 2011; 15 (2) :173-181
URL: http://ppj.phypha.ir/article-1-652-en.html
Dynamic age-related changes of extracellular field potential of isolated AV-node of rabbit
Vahid Khori , Alimohammad Alizadeh , Mahsa Niknam , Hamid Reza Moheimani , Hamid Yazdi , Mona Pourabouk , Fakhri Badaghabadi , Shima Changizi , Mryam Rajaei , Mohsen Nayebpour
Abstract:   (12579 Views)
Introduction: Developmental changes in atrioventricular nodal conduction time and refractoriness have been shown in several studies. Prevalence of atrioventricular nodal reentrant tachycardia (AVNRT) is clearly age-dependent. The purpose of this study was to determine developmental changes of basic and frequency-dependent electrophysiological properties of the atrioventricular node (AV-node) in neonatal and adult rabbits. Methods: In this study, the effects of increasing age on the basic and rate-dependent properties of isolated perfused AV-node were analyzed in neonatal (2-week-old) and adult (12-week-old) New Zealand rabbits. Specific stimulation protocols of recovery, facilitation and fatigue were separately applied in each group (n=7). Unipolar extracellular field potential was recorded by a silver electrode (100 M). Results: The results showed that the basic nodal properties (ERP, FRP, WBCL and AHmax) were significantly shorter in neonates compared to the adult group. The magnitude of fatigue was also decreased in the neonatal group compared to control (18.9 ±3.3 vs. 11.1 ± 1.2 msec). Time constant of recovery of the adult group was significantly higher than the neonatal group (P<0.05). Conclusion: The results of this study showed that nodal basic and frequency-dependent properties are age-related and different developmental changes of slow and fast pathways are responsible for this behavior and may reveal the grater susceptibility of AVNRT in young adults compared to infants.
Keywords: Age, AV node, frequency-dependent properties, electrophysiology, recovery
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Type of Manuscript: Experimental research article | Subject: Cardiovascular Physiology/Pharmacology
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