AJP - Heart and Circulatory Physiology, Vol 252, Issue 4 714-H720, Copyright © 1987 by American Physiological Society
Venule distension properties in Wistar, Wistar-Kyoto, and spontaneously hypertensive rats
D. J. Lang and B. L. Johns
The purpose of this study was to determine whether venule distension
characteristics are modified in denervated venules in the spontaneously
hypertensive rat (SHR) during the developmental stage of hypertension. The
distension of denervated first-order venules (1V) and small collecting
veins (SCV) in the intestine of 7- to 8-wk-old SHR, Wistar-Kyoto (WKY), and
Wistar rats were measured with intravital microscopy during venous pressure
elevation. Diameter strain and distensibility were calculated for the 1V
and SCV from vessel diameter and servo-null pressure. The Wistar 1V
underwent larger strains and distensibilities than the WKY or SHR vessels,
which had similar characteristics. For the SCV, the Wistar and WKY strains
and distensibilities were similar, with the SHR different from these at
only certain pressure elevations. Thus no consistent patterns of altered
distension characteristics were found in denervated SHR SCV or 1V compared
with its controls. This study does not distinguish between changes in local
active and passive factors in the vessel wall which may influence
distension. Our results may be consistent with disease mechanisms in the 7-
to 8-wk-old SHR which leave these local factors unchanged or with
mechanisms which have local venular effects that counterbalance each other,
leaving the distension behavior of the denervated venules unchanged.
