• retinal blood flow;
  • vasomotion;
  • porcine arterioles;
  • in vitro experiments


Purpose:  To characterize vasomotion in porcine retinal arterioles in vitro using isobaric (pressure myograph) and isometric (wire myograph) methods.

Methods:  Pressure myograph: 208 small porcine retinal arterioles (outer diameter 68 ± 4 μm) were studied under isobaric conditions in a double-barrelled pipette system. Diameter changes of the arterioles were registered by video recordings. Wire myograph: 60 large porcine retinal arterioles (inner diameter 147 ± 1.6 μm) were studied under isometric conditions in a small vessel myograph for force measurements.

Results:  The rates of success in initiating vasomotion were 7.2% using the pressure myograph and 43% using the wire myograph (p < 0.001). The small vessels studied under isobaric conditions oscillated with a frequency of 0.014 Hz and the episodes lasted 6.0 ± 1.0 min, whereas the large vessels under isometric conditions oscillated with a significantly faster frequency of 0.043 Hz and lasted 32.1 ± 4.9 min (p = 0.026).

Conclusion:  Retinal vasomotion can be studied in vitro using both pressure myograph and wire myograph techniques. The wire myograph is superior to the pressure myograph in initiating and maintaining vasomotion in vitro.