isolated single rabbit atrioventricular nodal myocytes (part 2)

Flecainide has been observed to inhibit ICa,L in ventricular myocytes from frog and dog , and this raises the possibility that ICa,L may also be a substrate for flecainide action in the AVN. However, little if any information exists concerning the cellular mechanisms underlying the actions of flecainide in the AVN. Given the importance of ICa,L in the AVN action potential, the aim of this study was to investigate the actions of flecainide on AVN ICa,L by using a single cell preparation of rod- and spindle-shaped AVN myocytes developed in our laboratory. Choose a perfect online pharmacy where you could be shopping for zoloft antidepresant any time, being sure your medical conditions will be under your complete control every step of the way.

ANIMALS AND METHODSPreparation of cells for recording: Rod- and spindleshaped AVN myocytes were isolated from the hearts of male New Zealand White rabbits (1.5 to 2.5 kg) by using the method described by Hancox et al . Briefly, rabbits were killed by cervical dislocation and the heart removed rapidly. The heart was then perfused in a Langendorff fashion at a rate of 6 mL/min/g heart tissue at 37°C with a solution containing 750 |jM calcium (full details of the basic isolation solution can be found in 15). After 2 mins, the perfusing solution was switched to a calcium-free solution with 100 |iM EGTA added (not 100 mM as published ). After 4 mins perfusion with calcium-free solution, the heart was perfused for 6 mins with an enzyme-containing solution (1 mg/mL, collagenase [Type 1A, Worthington, Freehold, New Jersey, USA] plus 0.1 mg/mL protease [Type XIV, Sigma, Dorset, United Kingdom] with a total calcium concentration of 375 |jM).

Category: Antiarrhythmic agents Cardiology / Tags: Antiarrhythmic agents, Atrioventricular node, Flecainide, L-type calcium current, Single cell

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