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Pain tests provoke modality-specific cardiovascular responses in awake, unrestrained rats. Pain 2011 Feb;152(2):274-84

Date

10/15/2010

Pubmed ID

20943317

Pubmed Central ID

PMC3022106

DOI

10.1016/j.pain.2010.09.010

Scopus ID

2-s2.0-78651511763   11 Citations

Abstract

Nociception modulates heart rate (HR) and mean arterial pressure (MAP), suggesting their use of HR and MAP as indicators of pain in animals. We explored this with telemetric recording in unrestrained control and neuropathic (spinal nerve ligation) rats. Plantar stimulation was performed emulating techniques commonly used to measure pain, specifically brush stroke, von Frey fiber application, noxious pin stimulation, acetone for cooling, and radiant heating, while recording MAP, HR, and specific evoked somatomotor behaviors (none; simple withdrawal; or sustained lifting, shaking, and grooming representing hyperalgesia). Pin produced elevations in both HR and MAP, and greater responses accompanied hyperalgesia behavior compared to simple withdrawal. Von Frey stimulation depressed MAP, and increased HR only when stimulation produced hyperalgesia behavior, suggesting that minimal nociception occurs without this behavior. Brush increased MAP even when no movement was evoked. Cold elevated both HR and MAP whether or not there was withdrawal, but MAP increased more when withdrawal was triggered. Heating, consistently depressed HR and MAP, independent of behavior. Other than a greater HR response to pin in animals made hyperalgesic by injury, cardiovascular events evoked by stimulation did not differ between control and neuropathic animals. We conclude that (a) thermoregulation rather than pain may dominate responses to heat and cooling stimuli; (b) brush and cooling stimuli may be perceived and produce cardiovascular activation without nocifensive withdrawal; (c) sensations that produce hyperalgesia behavior are accompanied by greater cardiovascular activation than those producing simple withdrawal; and (d) von Frey stimulation lacks cardiovascular evidence of nociception except when hyperalgesia behavior is evoked.

Author List

Rigaud M, Gemes G, Abram SE, Dean C, Hopp FA, Stucky CL, Eastwood D, Tarima S, Seagard J, Hogan QH

Authors

Quinn H. Hogan MD Vice Chair, Professor in the Anesthesiology department at Medical College of Wisconsin
Cheryl L. Stucky PhD Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of Wisconsin
Sergey S. Tarima PhD Associate Professor in the Institute for Health and Equity department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Blood Pressure
Dermatologic Surgical Procedures
Disease Models, Animal
Heart Rate
Hyperalgesia
Ligation
Male
Neuralgia
Pain Measurement
Rats
Rats, Sprague-Dawley
Skin
Wakefulness
jenkins-FCD Prod-480 9a4deaf152b0b06dd18151814fff2e18f6c05280