» Articles » PMID: 10747197

Effect of Motor Unit Recruitment on Functional Vasodilatation in Hamster Retractor Muscle

Overview
Journal J Physiol
Specialty Physiology
Date 2000 Apr 4
PMID 10747197
Citations 21
Authors
Affiliations
Soon will be listed here.
Abstract

1. The effect of motor unit recruitment on functional vasodilatation was investigated in hamster retractor muscle. Recruitment (i.e. peak tension) was controlled with voltage applied to the spinal accessory nerve (high = maximum tension; intermediate = approximately 50% maximum; low = approximately 25% maximum). Vasodilatory responses (diameter times time integral, DTI) to rhythmic contractions (1 per 2s for 65s) were evaluated in first, second and third order arterioles and in feed arteries. Reciprocal changes in duty cycle (range, 2.5-25%) effectively maintained the total active tension (tension times time integral, TTI) constant across recruitment levels. 2. With constant TTI and stimulation frequency (40 Hz), DTI in all vessels increased with motor unit recruitment. DTI increased from distal arterioles up through proximal feed arteries. 3. To determine whether the effect of recruitment on DTI was due to increased peak tension, the latter was controlled with stimulation frequency (15, 20 and 40 Hz) during maximum (high) recruitment. With constant TTI, DTI then decreased as peak tension increased. 4. To explore the interaction between recruitment and duty cycle on DTI, each recruitment level was applied at 2.5, 10 and 20 % duty cycle (at 40 Hz). For a given increase in TTI, recruitment had a greater effect on DTI than did duty cycle. 5. Functional vasodilatation in response to rhythmic contractions is facilitated by motor unit recruitment. Thus, vasodilatory responses are determined not only by the total tension produced, but also by the number of active motor units.

Citing Articles

Capillary-Mitochondrial Oxygen Transport in Muscle: Paradigm Shifts.

Poole D, Musch T Function (Oxf). 2023; 4(3):zqad013.

PMID: 37168497 PMC: 10165549. DOI: 10.1093/function/zqad013.


Do skeletal muscle motor units and microvascular units align to help match blood flow to metabolic demand?.

Murrant C, Fletcher N, Fitzpatrick E, Gee K Eur J Appl Physiol. 2021; 121(5):1241-1254.

PMID: 33538852 DOI: 10.1007/s00421-021-04598-4.


K channel activation links local vasodilatation with muscle fibre recruitment during exercise in humans.

Terwoord J, Hearon Jr C, Racine M, Ketelhut N, Luckasen G, Richards J J Physiol. 2020; 598(13):2621-2636.

PMID: 32329892 PMC: 7332407. DOI: 10.1113/JP279682.


Barium chloride injures myofibers through calcium-induced proteolysis with fragmentation of motor nerves and microvessels.

Morton A, Norton C, Jacobsen N, Fernando C, Cornelison D, Segal S Skelet Muscle. 2019; 9(1):27.

PMID: 31694693 PMC: 6833148. DOI: 10.1186/s13395-019-0213-2.


Skeletal muscle interstitial Po kinetics during recovery from contractions.

Hirai D, Craig J, Colburn T, Eshima H, Kano Y, Musch T J Appl Physiol (1985). 2019; 127(4):930-939.

PMID: 31369325 PMC: 6850987. DOI: 10.1152/japplphysiol.00297.2019.


References
1.
Hogan M, Ingham E, Kurdak S . Contraction duration affects metabolic energy cost and fatigue in skeletal muscle. Am J Physiol. 1998; 274(3):E397-402. DOI: 10.1152/ajpendo.1998.274.3.E397. View

2.
Berg B, Cohen K, Sarelius I . Direct coupling between blood flow and metabolism at the capillary level in striated muscle. Am J Physiol. 1997; 272(6 Pt 2):H2693-700. DOI: 10.1152/ajpheart.1997.272.6.H2693. View

3.
Kjellmer I . THE EFFECT OF EXERCISE ON THE VASCULAR BED OF SKELETAL MUSCLE. Acta Physiol Scand. 1964; 62:18-30. DOI: 10.1111/j.1748-1716.1964.tb03947.x. View

4.
Welsh D, Segal S . Muscle length directs sympathetic nerve activity and vasomotor tone in resistance vessels of hamster retractor. Circ Res. 1996; 79(3):551-9. DOI: 10.1161/01.res.79.3.551. View

5.
Delashaw J, Duling B . A study of the functional elements regulating capillary perfusion in striated muscle. Microvasc Res. 1988; 36(2):162-71. DOI: 10.1016/0026-2862(88)90016-7. View