title: Suppression of activation of muscle sympathetic nerve during non-noxious local cooling after the end of local cooling in normal adults.
abstract: OBJECTIVE
  While non-noxious local cooling is widely used in physical medicine, its effect on muscle sympathetic nerve activity (MSNA) and cardiovascular regulation are not clear. The purpose of the present study was to assess the responses of MSNA, blood pressure (BP), heart rate (HR) and local blood flow during non-noxious local cooling.
  
  
  METHODS
  The study included two protocols. Both protocols consisted of 10-min rest in supine position, followed by 15-min local cooling (15 °C) of the shin and anterior foot, and 20-min recovery. MSNA of the right common peroneal nerve, BP, HR, and shin skin temperature (TSK) were recorded in eight men in the first protocol, while leg blood flow (LBF) was measured in the same subjects by strain-gauge plethysmography in the second protocol.
  
  
  RESULTS
  TSK gradually decreased from 31.5 ± 0.02 to 16.0 ± 1.01 °C (mean ± SEM) during local cooling, and gradually increased after the end of local cooling. No subject complained of pain, and BP and HR remained constant. The MSNA burst rate increased significantly (p < 0.05) to 141.1 ± 12.5 % during local cooling, but decreased significantly (p < 0.05) to 73.6 ± 5.9 % during the recovery period. Total MSNA also increased to 148.0 ± 14.2 % (p < 0.05) during local cooling, and decreased to 74.0 ± 13.9 % (p < 0.05) at recovery. LBF remained constant through the experiment.
  
  
  CONCLUSIONS
  The results suggest that MSNA is activated by non-noxious local cooling, and attenuated after the end of local cooling without any changes in HR and BP.
authors.affiliation: Department of Rehabilitation Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ishida
authors.affiliation: Department of Rehabilitation Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, Wakayama, 641-8509, Japan. take-n@wakayama-med.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Health Sciences, Kansai University of Health Sciences, Osaka, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Department of Rehabilitation Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Nami
authors.initials: N
authors.lastname: Kanno
authors.affiliation: Department of Rehabilitation Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Noriyo
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Department of Rehabilitation Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Yoshi-Ichiro
authors.initials: Y
authors.lastname: Kamijo
authors.affiliation: Department of Rehabilitation Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Tajima
mesh_terms: D000328:Adult; D001794:Blood Pressure; D006339:Heart Rate; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D012039:Regional Blood Flow; D012881:Skin Temperature; D013564:Sympathetic Nervous System / Q000502:physiology*
keywords: Local cooling; Microneurography; Muscle blood flow; Plethysmography; Regional blood flow