The interface between inhibition of descending noradrenergic pain control pathways and negative affects in post-traumatic pain patients

Abstract

BackgroundAnimal studies have shown that surgical trauma activates the descending noradrenergic pathway. However, perioperative patients have decreased concentrations of noradrenaline (NA) in the cerebrospinal fluid (CSF). We proposed that the descending monoaminergic pathway is altered in post-traumatic pain patients and that CSF monoamine neurotransmitters may be more closely related to affective symptoms. We investigated the levels of monoamine neurotransmitters and assessed pain in these patients.MethodsPatients were divided into a post-traumatic pain group, a pain-free group, a painful labor group, and a pain-free labor group. CSF was collected from all patients, and concentrations of NA, 3-methoxy-4-hydroxyphenylglycol (MHPG), dopamine, homovanillic acid, and 5-hydroxyindoleacetic acid (5-HIAA) were measured by high-performance liquid chromatography.ResultsIn the post-traumatic pain group, lumbar CSF concentrations of NA and MHPG were significantly decreased (P < 0.01) compared to the control group. The post-traumatic pain group displayed a significant negative correlation between NA and the respective total value of the short form of the McGill pain questionnaire (SF-MPQ), SF-MPQ (affective), and visual analog scale (r = –0.388, r = –0.433, and r = –0.367; P < 0.05).ConclusionsPost-traumatic pain patients demonstrated decreased concentrations of NAin CSF, indicating that descending noradrenergic pain control pathways may be inhibited. NA is more closely related to negative affects in post-traumatic pain patients.

Assessing experimental visceral pain in dairy cattle: A pilot, prospective, blinded, randomized, and controlled study focusing on spinal pain proteomics

“…The latter could indicate sustained activation of the descending noradrenergic inhibitory pain pathway up to d 1-8, followed by fatigue of the same pathway. This was in line with previous studies that reported decreased CSF noradrenaline release following traumatic pain in patients (Cui et al, 2012). Nevertheless, CSF noradrenaline was a moderately effective pain biomarker because it did not differentiate between the 3 expected levels of analgesia.…”

Noradrenaline, Serotonin, GABA, and Glycine in Cerebrospinal Fluid during Labor Pain: A Cross-Sectional Prospective Study

“…It should be noted that this study showed no significant difference in CSF noradrenaline levels between the control and labor pain groups. In contrast, previous studies reported CSF noradrenaline level to be significantly decreased in patients with posttraumatic pain [ 8 ] and postsurgical pain [ 10 ], both of which are somatic pain. These findings make us question whether or not the descending noradrenergic pathways underlying the pain mechanisms of visceral pain and somatic pain are different.…”

“…In the present study, there was a significant decrease in CSF serotonin concentration in parturients with severe labor pain. Previous studies reported significant increase in CSF serotonin in pregnant women with painful active labor [visual analogue scale of 6.2 (IQR 4.8–7.6)]; however, the severity of pain was not intense [ 8 ]. It appears evident that the high level of pain intensity (NRS = 9) and the median pain duration of 325 minutes (5.4 hours) in the labor pain group in this study was sufficient to influence descending serotonergic control since an inverse correlation was observed between pain intensity and CSF serotonin level.…”

“…It appears evident that the high level of pain intensity (NRS = 9) and the median pain duration of 325 minutes (5.4 hours) in the labor pain group in this study was sufficient to influence descending serotonergic control since an inverse correlation was observed between pain intensity and CSF serotonin level. Moreover, negative emotional effects, including depression and stress, were found to be related with lower CSF serotonin level [ 8 ]. However, anxiety and depression and their relation to lower CSF serotonin concentration were not evaluated in this study.…”

“…Study in patients with posttraumatic pain found significantly decreased cerebrospinal fluid (CSF) concentration of noradrenaline and significantly increased CSF concentration of serotonin [ 8 ]. In pregnant women, CSF noradrenaline concentration was increased in parturients with labor pain, as compared to those without labor pain [ 9 ].…”