Objective: To investigate electrophysiology of cardiocytes in ligament of Marshall.
Methods: The single cardiocytes obtained from ligament of Marshall were direct observed under inverted microscope. The cardiocyte action potential and current density of I(Na), I(Ca), L, I(to), I(K) and I(K1) were researched by whole-cell patch-clamp techniques.
Results: There were two different cardiomyocytes in ligament of Marshall, one was rod shape, the other was short-rectangle shape. The short-rectangle myocyte was short and thick; the rod myocyte was long and thin. The short-rectangle myocyte was more than rod myocyte. The length/width rate of short-rectangle myocyte was less than that of rod myocyte (2.99 +/- 0.95 vs 12.05 +/- 2.41, P < 0.01). The action potential of ligament myocytes was similar to fast responsive cells. The action potential amplitude (APA) and duration (APD) of short-rectangle cells were less than those in rod cells. APA (mV), APD(50) (ms) and APD(90) (ms) were respectively 80.02 +/- 3.68 vs 91.72 +/- 7.56, 69.62 +/- 6.33 vs 83.14 +/- 3.66 and 107.55 +/- 4.25 vs 144.00 +/- 5.15, P < 0.05. The ion current density of I(Na), I(Ca), L, I(to), I(K1) was different between the two kind cells.
Conclusions: There are two different cardiocytes in ligament of Marshall. The action potential and ion current density of I(Na), I(Ca), L, I(to), I(K1) are different between the two kind cardiocytes.