title: Local and remote arteriolar dilations initiated by skeletal muscle contraction.
abstract: To investigate the relationship between skeletal muscle metabolism and arteriolar dilations in the region local to contracting muscle fibers as well as dilations at remote arteriolar regions upstream, we used a microelectrode on cremaster muscle of anesthetized hamsters to stimulate four to five muscle fibers lying approximately perpendicular to and overlapping a transverse arteriole. Before, during, and after muscle contraction, we measured the diameter of the arteriole at the site of muscle fiber overlap (local) and at a remote site approximately 1,000 microm upstream. Two minutes of 2-, 4-, or 8-Hz stimulation (5-10 V, 0.4-ms duration) produced a significant dilation locally (8.2 +/- 2.0-, 22.5 +/- 2.4-, and 30.9 +/- 2.1-microm increase, respectively) and at the remote site (4.2 +/- 0.8, 11.0 +/- 1.1, and 18.9 +/- 2.7 microm, respectively). Muscle contraction at 4 Hz initiated a remote dilation that was unaffected by 15-min micropipette application of either 2 microM tetrodotoxin, 0.07% halothane, or 40 microM 18-beta-glycyrrhetinic acid between the local and upstream site. Therefore, at the arteriolar level, muscle contraction initiates a robust remote dilation that does not appear to be transmitted via perivascular nerves or gap junctions.
authors.affiliation: Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Murrant
authors.forename: I H
authors.initials: IH
authors.lastname: Sarelius
mesh_terms: D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000502:physiology*; D006224:Cricetinae; D004558:Electric Stimulation; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology; D006034:Glycyrrhetinic Acid / Q000494:pharmacology; D006221:Halothane / Q000494:pharmacology; D008297:Male; D008647:Mesocricetus; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D008839:Microelectrodes; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology*; D009599:Nitroprusside / Q000494:pharmacology; D013395:Sucrose / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D009599:Nitroprusside; D013779:Tetrodotoxin; D013395:Sucrose; D006034:Glycyrrhetinic Acid; D006221:Halothane