Painful Conditioning Stimuli of the Craniofacial Region Evokes Diffuse Noxious Inhibitory Controls in Men and Women
- Autores: Kelun Wang, Peter Svensson, Lars Arendt Nielsen, Barry J. Sessle, Brian E. Cairns
- Localización: Journal of Oral & Facial Pain and Headache, ISSN-e 2333-0376, ISSN 2333-0384, Vol. 24, Nº. 3, 2010, págs. 255-261
- Idioma: inglés
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Resumen
Aims: To compare the modulatory effects of tonic mechanical or thermal craniofacial painful conditioning stimuli on pain sensitivity in craniofacial and spinal test sites in healthy men and women.
Methods: Mechanical and cold headbands were developed and tested on 12 healthy men and 12 age-matched women (mean ± SEM: 27 ± 1.5 years). The pressure applied by the mechanical headband around the skull above the eyebrows could be adjusted over time via feedback from a 0 to 10 electronic visual analog scale (VAS) to maintain the pain intensity at a given level for 10 minutes (3 to 7 on VAS). The cold headband consisted of a series of plastic bags filled with antifreeze water having a temperature of approx 3°C. During the 10 minutes of application, the subjects were asked to rate the pain intensity on a 10-cm VAS. Pressure pain thresholds (PPT) were recorded over the right and left masseter muscles (MAR, MAL), right splenius muscle (neck), right elbow (elbow), and right middle finger (finger) by a pressure algometer (1-cm2 area probe). The PPTs at each of the five sites were determined at baseline and during the mechanical or cold-induced pain. The two sessions with mechanical or cold headbands were performed at an interval of 30 minutes.
Results: Women had significantly lower absolute PPT values than men at most test sites (Unpaired t-test: P < .027). The mechanical headband caused pain in both men (peak pain mean ± SEM: 4.7 ± 0.4 cm) and women (4.9 ± 0.4 cm) (P = .455). A significant PPT elevation was found at MAR, MAL, neck, and finger in men (11% to 17%; P < .031) and at MAR, MAL, and neck in women (15% to 22%; P < .020) during the mechanical-induced pain. The cold headband caused pain in both men (4.0 ± 0.4 cm) and women (4.5 ± 0.4 cm) (P = .285). During the cold-induced pain, a significant PPT elevation was found at all test sites in men (P < .023) and at all sites (P < .021) except for the finger in women. The relative changes in PPT values were not significantly different between men and women at any test site (unpaired t-test: P > .446).
Conclusion: This study has documented that mechanical and thermal painful tonic stimuli applied to the craniofacial region can evoke diffuse noxious inhibitory control (DNIC)-like effects in the craniofacial region as well as spinally innervated areas, but without sex differences.
