Effects of chronic sympathectomy on vascular function in the human forearm.
To determine whether endothelial function is altered by chronic surgical sympathectomy, we infused ACh, isoproterenol, nitroprusside (NTP), and the nitric oxide synthase inhibitor NG-mono-methyl-L-arginine (L-NMMA) into the brachial arteries of nine patients 5-64 mo after thoracic sympathectomy for hyperhidrosis. Age- and gender-matched controls were also studied. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Lower body negative pressure was used to assess reflex vasoconstrictor responses. Tyramine, which acts locally and causes norepinephrine release from sympathetic nerves, was also administered via the brachial artery. FBF at rest was 2.5 +/- 0.4 ml x dl-1 x min-1 in the patients and 2.5 +/- 0.3 ml x dl-1 x min-1 in the controls (P = 0.95). The normal vasoconstrictor responses to lower body negative pressure were abolished in the patients. By contrast, tyramine produced dose-dependent vasoconstriction in the patients that was identical to that of controls. The dose-response curves to ACh were similar in patients and controls, with maximum values of 19.3 +/- 4.4 vs. 25.5 +/- 2.8 ml x dl-1 x min-1, respectively. L-NMMA reduced baseline FBF similarly and reduced the maximal FBF response to ACh in both groups (patients 8.9 +/- 3.5 vs. controls 9.7 +/- 2.5 ml x dl-1 x min-1). The vasodilation to isoproterenol was similar and blunted to the same extent in both groups by L-NMMA. The responses to NTP in patients and controls were similar and not affected by L-NMMA. We conclude that, in humans, chronic surgical sympathectomy does not cause major disruptions in vascular function in the forearm. The normal vasoconstrictor responses to tyramine indicate that there were viable sympathetic nerves in the forearm that were not engaged by LBNP.
Eisenach
John H
JH
Department of Anesthesiology, General Clinical Research Center, Mayo Clinic and Mayo Medical School, Rochester, Minnesota 55905, USA.
Clark
Erin S
ES
Charkoudian
Nisha
N
Dinenno
Frank A
FA
Atkinson
John L D
JL
Fealey
Robert D
RD
Dietz
Niki M
NM
Joyner
Michael J
MJ
D000328:Adult; D001916:Brachial Artery / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D005260:Female; D005542:Forearm / Q000098:blood supply* / Q000294:innervation / Q000502:physiology; D006801:Humans; D006945:Hyperhidrosis / Q000601:surgery; D007269:Injections, Intra-Arterial; D008150:Lower Body Negative Pressure; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000008:administration & dosage; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D013562:Sympathectomy; D013566:Sympathomimetics / Q000008:administration & dosage; D013995:Time; D014439:Tyramine / Q000008:administration & dosage; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014665:Vasodilator Agents / Q000008:administration & dosage; D014666:Vasomotor System / Q000187:drug effects / Q000502:physiology*; D019323:omega-N-Methylarginine / Q000008:administration & dosage
D004791:Enzyme Inhibitors; D013566:Sympathomimetics; D014665:Vasodilator Agents; D009599:Nitroprusside; D019323:omega-N-Methylarginine; D014439:Tyramine