title: Presence of nerve fiber collaterals from the sympathetic arteriolar plexus the concomitant venules in dog skeletal muscle.
abstract: Previous studies with the local 133Xenon washout method of the local regulation of blood flow in peripheral tissues in man gave evidence for a local veno-arteriolar sympathetic axon reflex which constricts arterioles when the venous transmural pressure is increased 25 mm Hg or more. The present study with the formaldehyde induced histofluorescence technique applied to skeletal muscle biopsies from dogs showed a dense plexus of noradrenergic sympathetic fibers around arterioles. Venules were generally devoid of these fibers. In certain instances sympathetic fibers left the arteriolar network to innervate the concomitant venule directly. Some of these fibers could be seen returning from the venule back to the arteriolar network. We suggest that the adrenergic fibers derived from the sympathetic plexus around the arterioles who innervate the venules can be the anatomical substrate for the local veno-arteriolar sympathetic axon reflex.
authors.affiliation: Institute of Medical Anatomy, University of Copenhagen, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Rygaard
authors.forename: M
authors.initials: M
authors.lastname: Møller
authors.forename: O
authors.initials: O
authors.lastname: Henriksen
mesh_terms: D000320:Adrenergic Fibers / Q000378:metabolism; D000818:Animals; D001160:Arterioles / Q000033:anatomy & histology / Q000294:innervation; D002395:Catecholamines / Q000378:metabolism; D004285:Dogs; D008297:Male; D008856:Microscopy, Fluorescence; D009132:Muscles / Q000033:anatomy & histology / Q000098:blood supply* / Q000294:innervation*; D014699:Venules / Q000033:anatomy & histology / Q000294:innervation
chemical_list: D002395:Catecholamines