BackgroundThe descending antinociceptive system (DAS) is thought to play crucial roles in the antinociceptive effect of spinal cord stimulation (SCS), especially through its serotonergic pathway. The nucleus raphe magnus (NRM) in the rostral ventromedial medulla is a major source of serotonin [5-hydroxytryptamine (5-HT)] to the DAS, but the role of the dorsal raphe nucleus (DRN) in the ventral periaqueductal gray matter is still unclear. Moreover, the influence of the noradrenergic pathway is largely unknown. In this study, we evaluated the involvement of these serotonergic and noradrenergic pathways in SCS-induced antinociception by behavioral analysis of spinal nerve-ligated (SNL) rats. We also investigated immunohistochemical changes in the DRN and locus coeruleus (LC), regarded as the adrenergic center of the DAS, and expression changes of synthetic enzymes of 5-HT [tryptophan hydroxylase (TPH)] and norepinephrine [dopamine β-hydroxylase (DβH)] in the spinal dorsal horn.ResultsIntrathecally administered methysergide, a 5-HT1- and 5-HT2-receptor antagonist, and idazoxan, an α2-adrenergic receptor antagonist, equally abolished the antinociceptive effect of SCS. The numbers of TPH-positive serotonergic and phosphorylated cyclic AMP response element binding protein (pCREB)-positive neurons and percentage of pCREB-positive serotonergic neurons in the DRN significantly increased after 3-h SCS. Further, the ipsilateral-to-contralateral immunoreactivity ratio of DβH increased in the LC of SNL rats and reached the level seen in naïve rats, even though the number of pCREB-positive neurons in the LC was unchanged by SNL and SCS. Moreover, 3-h SCS did not increase the expression levels of TPH and DβH in the spinal dorsal horn.ConclusionsThe serotonergic and noradrenergic pathways of the DAS are involved in the antinociceptive effect of SCS, but activation of the DRN might primarily be responsible for this effect, and the LC may have a smaller contribution. SCS does not potentiate the synthetic enzymes of 5HT and norepinephrine in the neuropathic spinal cord.

Acid instillation stimulates alveolar macrophages to produce tumor necrosis factor-alpha and nitric oxide. Pentoxifylline preserved innate production of tumor necrosis factor-alpha to lipopolysaccharide and did not inhibit the production of bactericidal nitric oxide. This may partly explain why pentoxifylline reduces acid aspiration-induced lung injury while maintaining the host's ability to combat bacterial infection after acid aspiration.

In both studies, XPS provided a significant improvement in PHN due to its prompt analgesia, lack of systemic side effects, and convenience of use.

Introduction Celiac plexus block is effective for treating intractable cancer pain and has been the focus of many studies. Several guiding techniques such as fluoroscopy, computed tomography, and endoscopy have been devised, and the target of the block has varied in previous studies as both the celiac plexus and splanchnic nerve, which is the main origin of the celiac plexus, have been targeted. At our affiliated institution, fluoroscopy-guided splanchnic nerve block with a single needle via transintervertebral disc approach is the first choice. However, there have been few reports on the use of this technique. This study investigated the efficacy and safety of this technique. Methods This multicenter retrospective observational study reviewed the medical records of patients who underwent neurolytic splanchnic nerve block (NSNB) via transintervertebral disc approach for intractable cancer pain at five tertiary hospitals in Japan from April 2005 to October 2020. The primary outcome was the clinical success ratio of NSNB, and the secondary outcome was the incidence ratio of NSNB-related adverse events. Results In total, 103 patients were included in the analysis. Of these, 77 patients met the definition of clinical success, with a ratio of 74.8%. The incidence ratio of NSNB-related adverse events was 40.8% (hypotension, 21.4%; alcohol intoxication, 13.6%; diarrhea, 11.7%; and vascular puncture, 3.9%; duplicates were present). All adverse events improved with observation and symptomatic treatment only. No patient had infection or serious adverse events such as organ or nerve damage. Conclusions The clinical success ratio of this technique was 74.8%. Although the incidence of adverse events was 40.8%, all events were mild and no serious adverse events were observed. The findings demonstrate the efficacy and safety of our NSNB in patients with intractable cancer pain.

Aims: To investigate rates of attention-deficit hyperactivity disorder (ADHD) in patients with chronic pain attending a pain clinic, the effects of a screening measure for ADHD in patients with chronic pain, and the effects of ADHD drugs on both pain and ADHD symptoms. Methods: We retrospectively surveyed 110 patients with chronic pain visiting the Anesthesiology and Pain Relief Center at the University of Tokyo in Japan, who had also consulted a psychiatrist, between April 2012 and July 2015. Results: Of the total of 110 patients with chronic pain, 35 (31.8%) were also diagnosed with ADHD, and the average Wender Utah Rating Scale (WURS) score among the ADHD patients was 39.0 ± 22.1 (n = 25). Only 36.0% of these patients exceeded the cutoff value, suggesting that 64.0% of the patients with ADHD were not identified by screening with the WURS. Twenty-six patients initiated treatment with ADHD medication, with dosage adjustment completed in 21. Of these 21 patients 20 (95.0%) had improved ADHD symptoms. Improved pain symptoms were observed in 14 patients (66.6%), with a reduction in the pain numerical rating scale of 64.7% ± 30.1%. Conclusions: This is the first study investigating the comorbidity of ADHD and chronic pain at pain clinics showing a high level of comorbidity and amelioration of pain and ADHD symptoms with treatment. Careful interpretation is required when the WURS is used to screen patients with chronic pain.