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Arteriolar network architecture and vasomotor function with ageing in mouse gluteus maximus muscle.
- Source :
-
The Journal of physiology [J Physiol] 2004 Dec 01; Vol. 561 (Pt 2), pp. 535-45. Date of Electronic Publication: 2004 Sep 23. - Publication Year :
- 2004
-
Abstract
- Physical diminishes with ageing, but little is known of how the microvascular supply to skeletal muscle fibres is affected. To test the hypothesis that ageing alters blood flow control, we investigated network architecture and vasomotor responses of arterioles in the gluteus maximus muscle of young (2-3 months), adult (12-14 months) and old (18-20 months) C57BL6 male mice (n = 83) (Young, Adult and Old, respectively). Microvascular casts revealed that the total number, length and surface area of arteriolar segments (diameter, 10-50 microm) were not significantly different across age-groups. However, for arterioles with diameter of 30 microm, tortuosity and branch angles increased with age (P < 0.05). In anaesthetized mice, second-order (2A) distributing arterioles had similar resting (17 +/- 1 microm) and maximal (37 +/- 1 microm) diameters and similar responsiveness to cumulative (10(-10)-10(-4) M) superfusion of acetylcholine or phenylephrine. With superfusate oxygen level raised from 0 to 21%, 2A arteriolar constriction in Young (11 +/- 1 microm) was greater (P < 0.05) than Adult and Old (5 +/- 1 microm). Observed 1 mm upstream from microiontophoresis of ACh (1 microA, 1 s), conducted vasodilatation was 10 +/- 1 microm in Young, 17 +/- 1 microm in Adult and 6 +/- 1 microm in Old (P < 0.05). With muscle contractions (2, 4 and 8 Hz; 30 s) arteriolar diameter increased similarly across age-groups (6 +/- 1, 11 +/- 1 and 18 +/- 1 microm, respectively). Muscle mass and active tension were similar across age-groups yet postcontraction vasodilatation recovered more rapidly in Old versus Adult and Young (P < 0.05). With arteriolar network architecture maintained during ageing, the impairment in conducted vasodilatation and attenuation of postcontraction vasodilatation may compromise exercise tolerance.
- Subjects :
- Acetylcholine pharmacology
Aging drug effects
Animals
Arterioles drug effects
Arterioles physiology
Buttocks blood supply
Buttocks physiology
Dose-Response Relationship, Drug
Male
Mice
Mice, Inbred C57BL
Muscle, Skeletal drug effects
Aging physiology
Muscle, Skeletal blood supply
Muscle, Skeletal physiology
Vasomotor System drug effects
Vasomotor System physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3751
- Volume :
- 561
- Issue :
- Pt 2
- Database :
- MEDLINE
- Journal :
- The Journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 15388783
- Full Text :
- https://doi.org/10.1113/jphysiol.2004.068262