Vasomotion frequency and amplitude related to intraluminal pressure and temperature in the wing of the intact, unanesthetized bat.
Spontaneous arteriolar vasomotion and its relation to intraluminal pressure and temperature were studied in the wing of the intact, unanesthetized bat, using intravital microscopy. Vasomotion was observed in all arterioles, terminal arterioles, and precapillary sphincters. Vasomotion was of the on-off-type in precapillary sphincters. No correlation existed between vasomotion amplitude and frequency. Stepwise changes in arterial and venous pressures, ranging from zero to +100 mm Hg and zero to -75 mm Hg, resulted in progressive decrease in rhythmic vasomotion frequency and amplitude. There was no change in the amplitude of vasomotion due to temperature elevation but there was an increase in vasomotion frequency. The precapillary vessels studied have similar vasomotion frequency and amplitude in control conditions, which are consistent and can be restored after interventions such as changes in intraluminal pressure and temperature. In addition, both vasomotion frequency and amplitude decrease in a similar fashion during stepwise changes in intraluminal pressure. These findings support the hypothesis that vasomotion, in these vessels, is due to a vascular pacemaker, which acts as a local oscillator that can be affected by temperature and by intraluminal pressure in a graded fashion.
Bouskela
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Department of Physiology and Biophysics, University of Washington, Seattle 98195.
D000818:Animals; D001160:Arterioles / Q000502:physiology; D001683:Biological Clocks; D002685:Chiroptera / Q000502:physiology*; D005260:Female; D008297:Male; D008833:Microcirculation / Q000502:physiology; D009068:Movement; D010507:Periodicity; D011312:Pressure; D013696:Temperature; D014921:Wings, Animal / Q000098:blood supply*