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Autonomic dysregulation and its prevention by voluntary exercise in a mouse model of chronic widespread pain (fibromyalgia)
Author(s) -
Sabharwal Rasna,
Rasmussen Lynn A.,
Sluka Kathleen A.,
Chapleau Mark W.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1147.4
Subject(s) - fibromyalgia , medicine , heart rate , autonomic nervous system , vasomotor , endocrinology , hyperalgesia , heart rate variability , physical therapy , blood pressure , nociception , anesthesia , receptor
Chronic widespread pain (CWP) as occurs in fibromyalgia is relatively common and debilitating. Parasympathetic‐mediated heart rate variability (HRV) is decreased in people with fibromyalgia with reports of increased sympathetic activity that could contribute to pain by sensitizing nociceptors. Exercise training reduces pain in fibromyalgia. The aims of this study were to characterize autonomic dysregulation in an established mouse model of CWP ( Yokoyama et al., J Pain, 2007 ); and determine if short duration (5‐day) exercise training (voluntary wheel‐running) abrogates the autonomic dysfunction. CWP was induced in young (10–12 wks) C57BL/6 male mice by repeated intramuscular injections of acidic saline (pH 5, 5 days apart) combined with 2 h of fatiguing exercise. Blood pressure (BP) and HR were measured by telemetry when mice were inactive. Induction of CWP decreased parasympathetic‐mediated HRV (RMSSD) without affecting mean BP or sympathetic vasomotor tone measured by the depressor response to the ganglionic blocker chlorisondamine (Table, *P<0.05, CWP vs. Control, n=4–6). Five days of exercise prior to induction of CWP prevented secondary mechanical hyperalgesia in the paw (n=4) and the decrease in HRV (†P<0.05, Exerc+CWP vs. CWP, n=4–8); and also decreased HR, BP and sympathetic tone in control and CWP mice (P<0.05). We conclude: 1) This mouse model of CWP exhibits selective impairment of parasympathetic modulation of HR with preserved sympathetic vasomotor tone; 2) Voluntary wheel‐running decreases sympathetic tone, HR and BP in both groups of mice, and prevents the secondary hyperalgesia and decreased HRV in CWP mice; and 3) The results suggest that exercise training would improve autonomic function as well as reduce pain in humans with CWP. (HL14388, AR061371 )