The purinergic system plays an important role in pain transmission. Recent studies have suggested that activation of P2-purinergic receptors (P2Rs) may be involved in neuron-satellite glial cell (SGC) interactions in the dorsal root ganglia (DRG), but the details remain unclear. In DRG, P2X7R is selectively expressed in SGCs, which closely surround neurons, and is highly sensitive to 3’-O-(4-Benzoyl) benzoyl-ATP (BzATP). Using calcium imaging in intact mice to survey a large number of DRG neurons and SGCs, we examined how intra-ganglionic purinergic signaling initiated by BzATP affects neuronal activities in vivo. We developed GFAP-GCaMP6s and Pirt-GCaMP6s mice to express the genetically encoded calcium indicator GGCaM6s in SGCs and DRG neurons, respectively. The application of BzATP to the ganglion induced concentration-dependent activation of SGCs in GFAP-GCaMP6s mice. In Pirt-GCaMP6s mice, BzATP initially activated more large-size neurons than small-size ones. Both glial and neuronal responses to BzATP were blocked by A438079, a P2X7R-selective antagonist. Moreover, blockers to pannexin1 channels (probenecid) and P2X3R (A317491) also reduced the actions of BzATP, suggesting that P2X7R stimulation may induce the opening of pannexin1 channels, leading to paracrine ATP release, which could further excite neurons by acting on P2X3Rs. Importantly, BzATP increased the responses of small-size DRG neurons and wide-dynamic range spinal neurons to subsequent peripheral stimuli. Our findings suggest that intra-ganglionic purinergic signaling initiated by P2X7R activation could trigger SGC-neuron interaction in vivo and increase DRG neuron excitability.

Accumulating evidence has shown that chronic cerebral ischemia (CCI) is one of the major causes of vascular dementia (VD) characterized by dysregulated cholesterol homeostasis and lipoprotein disturbances. Positive value of lipid-lowering agents has been widely evaluated for the treatment of VD. In the present study, we investigated whether Daming capsule (DMC) protected against CCI-induced VD and its possible mechanisms of action. DMC is a multi-herbal formula composed of Rheum palmatum L., Cassia obtusifolia L., Salvia miltiorrhiza, and Panax ginseng C.A., which has been used to treat hyperlipidemia for years in China. A network pharmacology method was established to reveal whether DMC contained any chemical constituent targeting CCI-related proteins. Furthermore, the potential anti-CCI effects of DMC (100 mg/kg or 200 mg/kg) administered for 30 days were investigated in vivo on rats that were subjected to permanent bilateral occlusion of the carotid arteries (2-VO). Spatial learning and memory abilities were evaluated using a Morris water maze (MWM) and morphological changes of cerebral cortex and hippocampus were assessed using hematoxylin and eosin staining. Moreover, the lipid peroxidation levels and antioxidative capabilities were measured using biochemical analysis. Our network pharmacology analysis revealed the existence of multiple CCI-related chemical-target interactions in DMC, suggesting a potential protective effect. An in vivo experiment verified that 200 mg/kg DMC improved cognitive deficits of 2-VO rats in the MWM test and attenuated pathological alterations in both the cerebral cortex and the hippocampus. Biochemical assays indicated that DMC decreased malondialdehyde levels and CCI-elevated superoxide dismutase activities, but increased the activities of glutathione peroxidase and catalase. Our findings suggested that DMC protected against cognitive dysfunction and nerve injuries caused by CCI, which is most likely related to its antioxidant actions.

Uncaria rhynchophylla (Gouteng in Chinese, GT) is the main medicine in many traditional recipes in China. It is commonly used to alleviate central nervous system (CNS) disorders, although its mechanism in Alzheimer’s disease is still unknown. This study was designed to predict and validate the underlying mechanism in AD treatment, thus illustrating the biological mechanisms of GT in treating AD. In this study, a PPI network was constructed, KEGG analysis and GO analysis were performed, and an “active ingredient-target-pathway” network for the treatment of Alzheimer’s disease was constructed. The active ingredients of GT were screened out, and the key targets were performed by molecular docking. UHPLC-Q-Exactive Orbitrap MS was used to screen the main active ingredients and was compared with the network pharmacology results, which verified that GT did contain the above ingredients. A total of targets were found to be significantly bound up with tau, Aβ, or Aβ and tau through the network pharmacology study. Three SH-SY5Y cell models induced by okadaic acid (OA), Na₂S₂O₄, and H₂O₂ were established for in vitro validation. We first found that GT can reverse the increase in the hyperphosphorylation of tau induced by OA to some extent, protecting against ROS damage. Moreover, the results also indicated that GT has significant neuroprotective effects. This study provides a basis for studying the potential mechanisms of GT in the treatment of AD.

Patients with vascular dementia experience more pain than healthy elders, potentially due to the presence of central neuropathic pain. However, the mechanisms underlying neuropathic pain in vascular dementia remain poorly understood, and there is currently a lack of effective treatment available. In this study, a rat model of vascular dementia was induced by permanently occluding the common carotid arteries bilaterally (2-VO). The cognitive impairments in the 2-VO rats were evaluated using the Morris Water Maze test, while HE and LBF staining were employed to assess brain tissue lesions in the hippocampal, cerebral cortex, and white matter regions known to be associated with severe memory and learning deficits. Furthermore, pain-related behavioral tests, including mechanical and thermal stimuli assessments, were conducted, and in vivo electrophysiological recordings of primary sensory neurons were performed. Compared to sham-operated and pre-operative rats, rats with vascular dementia exhibited mechanical allodynia and thermal hyperalgesia 30 days after surgery. Furthermore, in vivo electrophysiology revealed a significant increase in the occurrence of spontaneous activity of Aβ- and C-fiber sensory neurons in the rat model of vascular dementia. These results indicate that neuropathic pain behaviors developed in the rat model of vascular dementia, and abnormal spontaneous discharges of primary sensory neurons may play a crucial role in the development of pain after vascular dementia.

Demyelination diseases are characterized by injury to large (A-type) myelinated nerve fibers, and by secondary damage to small (C-type) sensory fibers, whi