Quantitative capillary topography and blood flow in the cerebral cortex of cats: an in vivo microscopic study - PubMed (original) (raw)

Quantitative capillary topography and blood flow in the cerebral cortex of cats: an in vivo microscopic study

G Pawlik et al. Brain Res. 1981.

Abstract

In 50 anesthetized cats the microcirculation in intermediate and deeper layers of the cerebral cortex was visualized in vivo by microtransillumination, and documented by high-speed microcinephotography. The viability of the preparation was verified in a series of experiments demonstrating spontaneous vasomotion and responsiveness to chemical stimulation of pial arterioles and small arteries. Stereological methods for quantitative analysis of projected images of capillaries in a comparatively large tissue volume were employed to determine morphometric and topographical parameters of the asymmetric, highly tortuous intracortical capillary network. Capillary diameters (5.1 +/- 0.84 micrometer), radii of curvature (median 57 micrometer), total capillary lengths per tissue volume 939 +/- 338.2 mm/cu.mm), capillary volume fractions (2.1 +/- 0.51%), total capillary surface areas per tissue volume (15.3 +/- 4.85 sq.mm/cu.mm), and intercapillary distances (median 24.2 micrometer) showed significant interregional differences. The frequency distribution of the lengths of capillary segments (median 108 micrometer) was best described by a Weibull distribution. On the average 90% of all capillaries were continuously perfused. Capillary red cell flow (median velocity 1500 micrometer/sec) was predominantly unidirectional and conspicuously irregular. The variance of capillary red cell velocities (CRCVs) was significantly correlated (tau = 0.48) with capillary tortuosity. An extreme value distribution best described the observed frequency distribution of CRCVs. Flow irregularities represented both white noise and a significant stochastic periodicity at frequencies between 40 and 90 Hz.

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