Ventromedial prefrontal neurokinin 1 receptor availability is reduced in chronic pain.
Neurokinin 1 (NK1) receptors are involved in pain and anxiety behaviors in animals, but little is known about central alterations in this receptor system in human pain. With positron emission tomography, using a [11]-Carbon labeled NK1 receptor antagonist, we demonstrate attenuated NK1 receptor availability in frontal, insular and cingulate cortex, as well as the hippocampus, amygdala and the periaqueductal gray area in patients with chronic pain. The reduced availability was most pronounced in the ventromedial prefrontal cortex (vmPFC), where attenuations correlated to measures of fear and avoidance of movement. Further, vmPFC NK1 levels also displayed opposing influences in patients as compared to controls on regional cerebral blood flow in the anterior cingulate. We conclude that the central NK1 receptor system is altered in human chronic pain. The results suggest that NK1 receptors in the vmPFC modulate motor inhibition, and contribute to fear and avoidance of movement.
Department of Psychology, Uppsala University, Uppsala, Sweden Uppsala Imanet AB, GE Healthcare, Uppsala, Sweden Department of Physiotherapy, School of Health, Care and Social Welfare, Mälardalen University, Västerås, Sweden Section of Physiotherapy, Department of Neuroscience, Uppsala University, Sweden Laboratory of Pain Research, Department of Surgical Sciences, Division of Anaesthesiology and Intensive Care Medicine, Uppsala University Hospital, Sweden Department of Biochemistry and Organic Chemistry, Uppsala University, Sweden Neuropsychopharmacology Section, Faculty of Medicine, Imperial College, London, UK.
Clas
C
Linnman
Lieuwe
L
Appel
Tomas
T
Furmark
Anne
A
Söderlund
Torsten
T
Gordh
Bengt
B
Långström
Mats
M
Fredrikson
D000328:Adult; D002908:Chronic Disease; D015536:Down-Regulation; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain / Q000209:etiology / Q000378:metabolism*; D017397:Prefrontal Cortex / Q000378:metabolism*; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D014911:Whiplash Injuries / Q000150:complications / Q000378:metabolism*
D018040:Receptors, Neurokinin-1