Exampel 1: Spontaneous and Stiimulus-evoked pacing Responses in Primary Myocyte Cultures
A.Fluorescence micrograph of myocytes cultured
on a MED-P545A probe (450 µm inter-electrode
spacing)
B. Spontaneous responses obtained from 64
electrodes. Calibration: 0.5mV, 10ms
C.Pacing responses were evoked by electric
stimulation using two electrodes on the MED
probe (arrow). Calibration: 0.5mV, 10ms
D.Phase map of the pacing activity. Each contour
shows the latency (ms) of the responses evoked
by stimulation.
Courtesy of Drs. Lee and Kodama, Nagoya University, Japan
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Example 2: Pacing on rat acute atrial tissue
[Left] Micrograph of a slice from rat atrial tissue on MED-P545A probe (450
µm inter-polar distance
[Right] Pacing responses were evoked by electric stimulation to the two
electrodes on MED probe.
Propagation of the pacing activity. Each
time frame shows the computed two dimensional
field potential distribution
over time. The times after the stimulation
are shown in each panel. Positive
potentials are white and negatives are
black.
Courtesy of Dr. H.Yeh,
Mackay Memorial Hospital, Taiwan
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Example 3: Recordings from Smooth Muscle
Spontaneous potentials exhibited by a smooth muscle (circular & longitudinal) preparation obtained from a small segment of guinea pig intestine. The preparation was placed on a MED64 electrode array (450 µm inter-electrode spacing and held down using netting and slice anchors (as typically done with brain slices).
(a) This series of frames illustrates the spread of pacemaker activity seen along circular muscle in the presence of 1 µMNifedipineand 250 nMTTX. The voltages recorded at each electrode are pseudo-color coded (scale at right) and oriented as shown in the first panel. The frames were taken 50 msec apart, and are displayed temporally from left to right for the top, and then the bottom rows. As shown, the peak negativities (yellow) spread along the orientation of the circular muscle (left to right), which was preferentially oriented to be in closest contact with the electrode array.
(b) Latency maps of the peak negativity (left graph) and positivity(right graph) also illustrate the phase differences observed in spontaneous pacemaker activity. The phase map of the negative peak is, as shown in a, consistent with the spread of pacemaker activity along the direction in which the circular muscle is oriented. The map of the positive peak is consistent with this, but also suggests spread along the direction (bottom to top) of the longitudinal muscle.
Courtesy of Dr. Nakayama, Dept. of Cell Physiology, Graduate school of medicine, Nagoya University, Japan
