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Microvascular flow routes in muscle controlled by vasoconstrictors

journal contribution
posted on 2023-05-16, 17:21 authored by Lejun ZhangLejun Zhang, Newman, JMB, Stephen RichardsStephen Richards, Stephen RattiganStephen Rattigan, Michael ClarkMichael Clark
Vasoconstrictors can either increase or decrease metabolism of the constant flow pump-perfused rat hindlimb. In addition, there is indirect evidence from vascular casts, surface fluorometry, dye entrapment studies, and fluorescent microsphere mapping of flow that this may be due to redistribution of flow between putatively nutritive and non-nutritive routes within muscle. In the present study, we used two methods in an attempt to identify perfused nutritive and non-nutritive vessels in muscle sections: (i) a combination of perfusion fixation with glutaraldehyde and post-perfusion Griffonia simplicifolia lectin and (ii) perfusion with rhodamine-dextran70 (lysine fixable) and post-fixation with formaldehyde. Perfusions involved vehicle only (control, a mix of nutritive and non-nutritive flow), 15 nM angiotensin II (AII) to increase, or 1 μM serotonin (5-HT) to decrease nutritive flow. Microscopic examination of muscle sections following AII showed an increase in perfused capillaries with fewer areas of under-perfusion, relative to control. In contrast, 5-HT caused a marked decrease in perfused capillaries relative to control and evidence that flow was carried by connective tissue vessels that on average were of greater diameter and were more sparsely distributed than capillaries. It is concluded that vasoconstrictors that alter hindlimb metabolism do so by intra-muscle redistribution between capillaries (nutritive) and non-nutritive (connective tissue) vessels within each muscle. © 2005 Elsevier Inc. All rights reserved.

Funding

National Health & Medical Research Council

History

Publication title

Microvascular Research

Volume

70

Pagination

7-16

ISSN

0026-2862

Department/School

Tasmanian School of Medicine

Publisher

Academic Press

Place of publication

New York

Repository Status

  • Restricted

Socio-economic Objectives

Clinical health not elsewhere classified

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