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Maturation is associated with changes in rat cerebral artery structure, biomechanical properties and tone
Author(s) -
Mandalà M.,
Pedatella A. L.,
Morales Palomares S.,
Cipolla M. J.,
Osol G.
Publication year - 2012
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2011.02406.x
Subject(s) - elastin , lumen (anatomy) , ageing , vasodilation , anatomy , medicine , endothelium , basilar artery , endocrinology , cerebral arteries , chemistry , cardiology , pathology
Aim: This study evaluated the hypothesis that physiological maturation affects cerebral artery smooth muscle–endothelial interactions involved in pressure‐induced tone and alters the dimensional and biomechanical properties of small posterior cerebral arteries ( PCA ). Methods: Secondary branches of PCA from young (4–5 weeks old, n = 11), adult (14–16 weeks old, n = 11) and mature (44–47 weeks old, n = 11) male S prague‐ D awley rats were isolated, cannulated, pressurized and subjected to a range of intraluminal pressures (10–110 mm Hg ) to determine tone with and without pharmacologic nitric oxide synthase ( NOS ) inhibition. Measurements of passive lumen diameter and wall thickness as a function of pressure were used to determine changes in structure, distensibility and wall stress; histological analysis was performed on vessel cross‐sections to assess collagen and elastin contents. Results: Although pressure‐dependent tone decreased significantly during ageing, differences between groups were abolished by NOS inhibition. Vessel diameters increased in adult vs. young rats (at 90 mmHg, 233 ± 6.0 μm vs. 192 ± 4.5 μm; P < 0.05), possibly secondary to somatic growth. Further ageing was associated with reductions in lumen diameter (207 ± 6.5 μm; P < 0.05), increased wall and media thickness (and wall/lumen ratio) and cross‐sectional area. Distensibility and wall collagen were unchanged, although elastin content was significantly reduced. Conclusions: Maturation is associated with differences in PCA dimensional properties that indicate a pattern of initial outward eutrophic, followed by inward hypertrophic remodelling. Functionally, the contribution of basal NO increases with age in a way that reduces pressure‐dependent tone and diminishes vasodilator reserve.