title: Interaction between conducted vasodilation and sympathetic nerve activation in arterioles of hamster striated muscle.
abstract: We tested the hypothesis that sympathetic nerve activity can influence the conduction of vasodilation along the arteriolar wall. Arterioles in the superfused cremaster muscle of anesthetized male hamsters (n = 21, 109 +/- 4 g) were studied. Microelectrodes were positioned adjacent to the distal end of primary arterioles to stimulate sympathetic nerves throughout arteriolar networks (perivascular nerve stimulation [PNS]). Microiontophoresis micropipettes (tip outer diameter, 1 to 2 microns) filled with acetylcholine (ACh, 1 mol/L) were positioned adjacent to the wall of second-order (2A) or third-order (3A) arterioles approximately 1 mm distal to their origin to induce local and conducted vasodilation; diameter responses were recorded at the micropipette tip and at vessel origins, respectively. For 2A and 3A arterioles (resting diameters, 15 to 54 and 9 to 30 microns, respectively), vasoconstriction with PNS was frequency dependent (0.5 to 32 Hz); this was attenuated by 65% (P < .05) with alpha-adrenoceptor blockade (phentolamine, 1 mumol/L). Conducted vasodilation was attenuated by > 40% during 16-Hz PNS (P < .05); this effect was reversed by phentolamine. In a reciprocal fashion, conducted vasodilation diminished PNS-induced vasoconstriction by approximately 50% (P < .05). Elevating oxygen (from 0% to 10%) in the superfusion solution induced vasoconstriction similar to that with 16-Hz PNS yet had no effect on conduction. Neural blockade with tetrodotoxin (1 mumol/L) eliminated PNS-induced vasoconstriction and enhanced (P < .05) conducted vasodilation. These findings indicate that perivascular nerves in striated muscle can influence cell-to-cell communication along the arteriolar wall both at rest and during enhanced sympathetic activity.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: John B. Pierce Laboratory, Yale University School of Medicine, New Haven, CT 06519, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Kurjiaka
authors.forename: S S
authors.initials: SS
authors.lastname: Segal
mesh_terms: D000818:Animals; D001160:Arterioles / Q000378:metabolism / Q000502:physiology*; D006224:Cricetinae; D008297:Male; D008833:Microcirculation; D018715:Microscopy, Video; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000098:blood supply / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*