Pain and analgesia: The dual effect of nitric oxide in the nociceptive system (original) (raw)

The role of nitric oxide in nociception

Current Pain and Headache Reports, 2000

Pharmacologic, electrophysiologic, and immunohistochemical studies have suggested a role of nitric oxide (NO) in nociception processing. Recent studies have indicated that NO may modulate spinal and sensory neuron excitability through multiple mechanisms that may underlie its distinctive roles in different pain states. Differential regulation of a family of NO-producing enzymes, NO synthases, contributes mainly to the complexity underlying the role of NO in nociception. This review summarizes the latest advances in our understanding of the contribution of NO to pain transduction. Possible cellular mechanisms regarding the connection between NO production and the abnormal sensation derived from different stimuli and pathologic conditions are discussed.

Pain modulation by nitric oxide in the spinal cord

Frontiers in Neuroscience, 2009

Nitric oxide (NO) is a versatile messenger molecule first associated with endothelial relaxing effects. In the central nervous system (CNS), NO synthesis is primarily triggered by activation of N-methyl-D-aspartate (NMDA) receptors and has a Janus face, with both beneficial and harmful properties. There are three isoforms of the NO synthesizing enzyme nitric oxide synthase (NOS): neuronal (nNOS), endothelial (eNOS), and inducible nitric oxide synthase (iNOS), each one involved with specific events in the brain. In the CNS, nNOS is involved with modulation of synaptic transmission through long-term potentiation in several regions, including nociceptive circuits in the spinal cord. Here, we review the role played by NO on central pain sensitization.

Role of nitric oxide in the regulation of pain after nociceptive stimuli in rat spinal cord

2018

Öz Purpose: In this study, we examined the responses of the neurons in the lumbar segments of the spinal cord to nociceptive stimuli induced by formalin using c-fos immunohistochemistry and NADPH-d histochemistry Materials and Methods: Thirteen male, Wistar albino rats were used. The rats were divided into 3 groups. Group 1: pain group (n=5). Group 2: sham group (n=5). Group 3: control group (n=3). In group 1, 50 μl of 30% formalin solution was injected subcutaneously unilaterally on the dorsal surface of the right foot. In group 2, phosphate buffered saline was injected subcutaneously unilaterally on the dorsal surface of the right foot. In group 3, no treatment was given. For each group lumbar spinal cord (SC) samples were taken. Samples were stained with c-fos and NADPH-d histochemistry and cfos/NADPH-d double-labeling methods and evaluated under light microscope. Results: We noted that cells on spinal cord sections stained with c-fos, NADPH-d and both became prominent with nocic...

Nitrous Oxide Persistently Alleviates Pain Hypersensitivity in Neuropathic Rats: A Dose-Dependent Effect

Pain Research and Management, 2015

BACKGROUND: Despite numerous pharmacological approaches, there are no common analgesic drugs that produce meaningful relief for the majority of patients with neuropathic pain. Although nitrous oxide (N2O) is a weak analgesic that acts via opioid-dependent mechanisms, it is also an antagonist of theN-methyl-D-aspartate receptor (NMDAR). The NMDAR plays a critical role in the development of pain sensitization induced by nerve injury.OBJECTIVE: Using the chronic constriction injury of the sciatic nerve in male rats as a preclinical model of neuropathic pain, the first aim of the present study was to evaluate the lowest N2O concentration and the shortest time of N2O postinjury exposure that would produce persistent relief of neuropathic pain. The second aim was to compare the effects of N2O with gabapentin, a reference drug used in human neuropathic pain relief.METHODS: Changes in the nociceptive threshold were evaluated using the paw pressure vocalization test in rats.RESULTS: Among th...