Sex-Related Differences in Human Pain and Rat Afferent Discharge Evoked by Injection of Glutamate Into the Masseter Muscle

Journal of Neurophysiology - Tập 86 Số 2 - Trang 782-791 - 2001
Brian E. Cairns1, James W. Hu1, Lars Arendt‐Nielsen2, Barry J. Sessle1, Peter Svensson2,3
1Faculty of Dentistry, The University of Toronto, Toronto, Ontario, M5G 1G6 Canada
2Center for Sensory-Motor Interaction, Laboratory for Experimental Pain Research, Aalborg University, DK-9220 Aalborg; and
3Department of Prosthetic Dentistry and Stomatognathic Physiology, Orofacial Pain Clinic, Royal Dental College, Aarhus University, DK-8000 Aarhus, Denmark

Tóm tắt

Animal studies have suggested that tissue injury–related increased levels of glutamate may be involved in peripheral nociceptive mechanisms in deep craniofacial tissues. Indeed, injection of glutamate (0.1–1 M, 10 μl) into the temporomandibular region evokes reflex jaw muscle responses through activation of peripheral excitatory amino acid receptors. It has recently been found that this glutamate-evoked reflex muscle activity is significantly greater in female than male rats. However, it is not known whether peripheral administration of glutamate, in the same concentrations that evoke jaw muscle activity in rats, causes pain in humans or activates deep craniofacial nociceptive afferents. Therefore we examined whether injection of glutamate into the masseter muscle induces pain in male and female volunteers and, since masseter afferent recordings were not feasible in humans, whether glutamate excites putative nociceptive afferents supplying the masseter muscle of male and female rats. Injection of glutamate (0.5 M or 1.0 M, 0.2 ml) into the masseter muscle of both men and women caused significantly higher levels of peak pain, duration of pain, and overall pain than injection of isotonic saline (0.2 ml). In addition, glutamate-evoked peak and overall muscle pain in women was significantly greater than in men. In rats of both sexes, glutamate (10 μl, 0.5 M) evoked activity in a subpopulation of masseter muscle afferents ( n = 36) that projected to the subnucleus caudalis, an important relay of noxious input from the craniofacial region. The largest responses to glutamate were recorded in muscle afferents with the slowest conduction velocities (2.5–5 m/s). Further, glutamate-evoked masseter muscle afferent activity was significantly greater in female than in male rats. These results indicate that glutamate injection into the masseter muscle evokes pain responses that are greater in women than men and that one possible mechanism for this difference may be a greater sensitivity to glutamate of masseter muscle afferents in females. These sex-related differences in acute experimental masseter muscle pain are particularly interesting given the higher prevalence of many chronic muscle pain conditions in women.

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Tài liệu tham khảo

10.1016/0006-8993(89)91573-4

Bennett RM, 1995, Compr Ther, 21, 269

Bereiter DA, 1998, Soc Neurosci Abstr, 24, 389

10.1016/S1082-3174(11)80024-3

10.1016/0304-3959(93)90058-W

10.1152/jn.1996.75.3.1152

10.1523/JNEUROSCI.18-19-08056.1998

10.1152/jn.1999.81.4.1966

10.1152/jn.2001.85.6.2446

10.1002/cne.902790302

10.1016/S0304-3959(98)00063-3

10.1016/0304-3940(95)11889-5

10.1111/j.1365-2842.1995.tb00246.x

10.1016/S0022-3913(98)70073-3

Dao TTT, 2000, J Orofacial Pain, 14, 169

10.1016/0006-8993(81)91297-X

10.1016/S0304-3959(00)00362-6

Dworkin SF, 1992, J Craniomandib Disord, 6, 301

10.1097/00002508-199909000-00011

10.1016/S0304-3959(99)00233-X

10.1016/S0304-3959(97)00214-5

10.1016/S0149-7634(00)00017-8

Fillingim RB, 2000, Sex, Gender, and Pain, Progress in Pain Research and Management, 17, 191

10.1016/0006-8993(76)90593-X

10.1016/0031-9384(92)90400-V

10.1016/S0304-3959(96)03243-5

10.1016/0304-3959(89)90029-8

10.1016/0304-3959(92)90131-T

10.1016/0014-2999(95)00449-U

Isselee H, 1998, J Orofacial Pain, 12, 203

10.1161/01.RES.50.1.133

10.1113/jphysiol.1977.sp012088

10.1016/S0304-3959(99)00311-5

10.1016/S0014-2999(97)00072-1

10.1016/S0304-3959(96)03230-7

10.1097/00000542-199006000-00012

10.1523/JNEUROSCI.13-10-04511.1993

10.1016/0304-3959(95)00068-2

10.1016/S0006-8993(96)00851-7

10.1016/0031-9384(94)90040-X

McNearney T, 2000, J Rheumatol, 27, 739

10.1113/jphysiol.1977.sp011802

10.1016/0304-3959(93)90027-M

10.1016/0006-8993(86)91148-0

10.1113/jphysiol.1960.sp006486

10.1139/y98-121

10.1111/j.1365-2842.1998.00270.x

10.1016/0306-4522(88)90357-0

10.1016/S0304-3959(97)00199-1

Salonen L, 1990, J Craniomandib Disord, 4, 241

Sessle BJ, 1999, J Orofacial Pain, 13, 238

10.1177/10454411000110010401

10.1002/cne.902680403

10.1152/jn.1994.72.2.883

10.1523/JNEUROSCI.12-01-00086.1992

Stohler CS, 1999, J Orofacial Pain, 13, 273

10.1016/S0304-3959(98)00171-7

10.1016/0304-3959(95)00133-6

Svensson P, 1995, J Orofacial Pain, 9, 347

10.1016/S0304-3959(97)00156-5

10.1016/S0304-3959(99)00124-4

10.1016/S0304-3959(96)03181-8

10.1109/10.222327

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Journal of Neurophysiology

Tập 86 Số 2

782-791

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