ABSTRACT
Dilatation of rat pial arterioles at constant arteriolar wall strain during autoregulation of cerebral circulation was shown by the method of biomicroscopy. Wavelet-analysis of cerebral blood flow oscillations during this period revealed increased oscillation amplitude in the endothelial and neurogenic frequency ranges and unchanged amplitude at myogenic frequency range. These findings probably attest to the leading role of myogenic reaction in the autoregulation.
Subject(s)
Arterioles/physiology , Brain/blood supply , Cerebrovascular Circulation/physiology , Muscle, Smooth, Vascular/physiology , Animals , Blood Flow Velocity/physiology , Blood Pressure , Laser-Doppler Flowmetry , Male , Microscopy , Muscle Tonus/physiology , RatsABSTRACT
The authors studied changes in erythrocyte membrane nanostructure using a rodent model of hemorrhagic hypotension and resuscitation. Both macro- and microstructural elements were examined using atomic force microscopy. Membrane "roughness" was characterized using spatial Fourier transformation and was stratified according to the periodicity of the membrane. Acute hemorrhage resulted in an increase in the diameter and height of erythrocytes, which returned to baseline levels by the end of the hemorrhagic hypotensive period. The effect of hypotension on the erythrocyte surface was nonuniform. In those regions where damage was considerable, the rate of restoration of the membrane microstructure to baseline levels was prolonged. The less damaged surfaces were restored more rapidly to control values after reperfusion. More detailed use of atomic force microscopy in the definition of the erythrocyte membrane microstructure may further define the mechanisms of cellular functional restoration after hemorrhage.
