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Postoperative pain after total knee arthroplasty (TKA) is a continuing problem despite optimised multimodal analgesia. Previous studies have shown preoperative glucocorticoids to reduce postoperative pain, but knowledge about specific doses and effects in specific patient groups is lacking.

The role of Aβ-afferents in somatosensory function is often oversimplified as low threshold mechanoreceptors (LTMRs) with large omission of Aβ-afferent involvement in nociception. Recently, we have characterized Aβ-afferent neurons which have large diameter somas in the trigeminal ganglion (TG) and classified them into non-nociceptive and nociceptive-like TG afferent neurons based on their electrophysiological properties. Here, we extend our previous observations to further characterize electrophysiological properties of trigeminal Aβ-afferent neurons and investigate their mechanical and chemical sensitivity by patch-clamp recordings from large-diameter TG neurons in ex vivo TG preparations of adult male and female rats. Based on cluster analysis of electrophysiological properties, trigeminal Aβ-afferent neurons can be classified into five discrete types (type I, IIa, IIb, IIIa, and IIIb), which responded differentially to mechanical stimulation and sensory mediators including serotonin (5-HT), acetylcholine (ACh) and adenosine triphosphate (ATP). Notably, type I neuron action potential (AP) was small in amplitude, width was narrow in duration, and peak dV/dt repolarization was great with no deflection observed, whereas discretely graded differences were observed for type IIa, IIb, IIIa, and IIIb, as AP increased in amplitude, width broadened in duration, and peak dV/dt repolarization reduced with the emergence of increasing deflection. Type I, IIa, and IIb neurons were mostly mechanically sensitive, displaying robust and rapidly adapting mechanically activated current (IMA) in response to membrane displacement, while IIIa and IIIb, conversely, were almost all mechanically insensitive. Interestingly, mechanical insensitivity coincided with increased sensitivity to 5-HT and ACh. Together, type I, IIa and IIb display features of LTMR Aβ-afferent neurons while type IIIa and type IIIb show properties of nociceptive Aβ-afferent neurons.

Migraine is a type of primary headache caused by changes in the trigeminal system and has been reported to be associated with neurovascular inflammation of cerebral and extracerebral vessels.

Sensory neuron hyperexcitability is a critical driver of pathological pain and can result from axon damage, inflammation, or neuronal stress. G-protein coupled receptor (GPCR) signaling can induce pain amplification by modulating the activation of Trp-family ionotropic receptors and voltage-gated ion channels. Here, we sought to use calcium imaging to identify novel inhibitors of the intracellular pathways that mediate sensory neuron sensitization and lead to hyperexcitability. We identified a novel stimulus cocktail consisting of L-054,264, a SST2R agonist, and CYM5541, a S1PR3 agonist, that elicits calcium responses in mouse primary sensory neurons in vitro as well as pain and thermal hypersensitivity in mice in vivo. We screened a library of 906 bioactive compounds and identified 24 hits that reduced calcium flux elicited by L-054,264/CYM5541. Among these hits, silymarin, a natural product derived from milk thistle, strongly reduced activation by the stimulation cocktail, as well as by a distinct inflammatory cocktail containing bradykinin and prostaglandin E2. Silymarin had no effect on sensory neuron excitability at baseline, but reduced calcium flux via Orai channels and downstream mediators of phospholipase C signaling. In vivo, silymarin pretreatment blocked development of adjuvant-mediated thermal hypersensitivity, indicating potential use as an anti-inflammatory analgesic.

Chronic headache disorders are a major cause of pain and disability. Education and supportive self-management approaches could reduce burden of headache disability. We tested the effectiveness of a group educational and supportive self-management programme for people living with chronic headaches.

Spondylolysis and isthmic spondylolisthesis are commonly implicated as organic causes of low back pain in this population. Many patients involved in sports that require repetitive hyperextension of the lumbar spine like diving, weightlifting, gymnastics and wrestling develop spondylolysis and isthmic spondylolisthesis. While patients are typically asymptomatic in mild forms, the hallmark of symptoms in more advanced disease include low back pain, radiculopathy, postural changes and rarely, neurologic deficits.

The objective of the current research study was to formulate the PEGylated lipid polymer hybrid nanoparticles of ergotamine and caffeine for intranasal administration with higher entrapment efficiency, better permeability, desirable controlled release pattern, and significant brain uptake in animal studies. A single-step nanoprecipitation method was employed in the processing of self-assembled hybrid nanoparticles constituting polymer PLGA, lipids soya lecithin, and DPPC with PEGylation using polyethylene glycol (PEG-2000). The optimal lipid/polymer weight ratio of 15% w/w showed lower particle size of 239.46 ± 2.31 nm with good colloidal stability depicted by zeta potential (- 18.36 ± 6.59 mV), higher entrapment efficiency of 86.88 ± 1.67%, and controlled release profile when evaluated for in vitro and ex vivo studies as 97.12 ± 2.79% and 75.13 ± 5.62% release, respectively, for 48 h. The formulation showed long-term serum stability when incubated in bovine serum albumin and displayed high brain uptake (4.35-fold) offering significant permeability in the brain post-intranasal administration via olfactory route. Histopathological investigations and serotonin toxicity studies in animals confirmed the safe and non-toxic nature of the formulation while the acetic acid writhing test proved the anti-hyperalgesic activity. The PEGylated lipid polymer hybrid nanoparticles of ergotamine and caffeine showed synergistic activity with efficacious higher anti-migraine potential.