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. Author manuscript; available in PMC: 2006 Jun 9.
Published in final edited form as: Curr Probl Cardiol. 2005 Jan;30(1):9–54. doi: 10.1016/j.cpcardiol.2004.04.005

Fig 5.

Fig 5

Differential effects of ischemia on action potentials recorded from endocardial and epicardial myocytes dissociated from the canine left ventricle. A: Control. B: Responses recorded after 30 min of superfusion with ischemic solution. “Ischemia” caused a marked abbreviation of APD90 in the epicardial cell and a modest shortening in the endocardial cell. C: Responses obtained 5 min after switching to an ischemic solution containing 4-aminopyridine (4-AP: 1 mM). 4-AP reversed the ischemia-induced shortening of APD90 in the epicardial myocyte and also prolonged APD90 in the endocardial cell. These effects of 4-AP were similar to those observed in syncytial tissue preparations from the corresponding ventricular layer. BCL of 800 msec. (From ref. 68 with permission.)