OBJECTIVE: To determine the relationship between pain provocation and level and disc degeneration in lumbar discography. METHOD: Seventy-one patients with lumbar discogenic pain and total 109 discography were studied. During contrast mediun injection, the patient's pain response was reported. The patients were invited to choose among the following options: 'no pain or only pressure feeling', 'dissimilar', 'similar', and 'exact'. And pain location was chosen among the followings: 'low back', 'buttock', 'anterior thigh', 'posterior thigh', and 'lateral thigh'. Correlation between degeneration and provocation response was analyzed. And discography level and provocation area were evaluated. RESULTS: Low back and buttock area was the most common provocation pain site, but it was not specific by disc level. And provocation pain frequently appeared in irregular and fissured types, but the existence of provocation pain was significantly low in ruptured type. CONCLUSION: There was no correlation between provocation pain area and discography level. And existence rate of provocation pain in ruptured disc was very low. It might be due to low mechanical compression with little stimulation of nociceptor. We suggested that if patients have a ruptured disc with chemical irritation, provocation pain was not a good indicator of diagnosis of discogenic back pain.
Back Pain ; Buttocks ; Diagnosis ; Humans ; Intervertebral Disc Degeneration* ; Nociceptors

Transient receptor potential (TRP) protein is a superfamily of cation channels which have 6 transmembrane domains and mainly pass calcium ion through themselves. There are seven types of subfamilies in the TRP superfamily. TRP channels can be activated by various kinds of stimuli. Some TRP channels are polymodal receptors because two or more types of stimuli can activate the same type of TRP channels. TRP proteins can play roles in a living organism as receptors for sensing outside stimuli or inside local stimuli of itself, as signal conductors, or as signal transducers. Especially, TRP channels have key roles in thermosensation, mechanosensation, taste, trigeminal olfaction and nociception. Therefore, TRP channels can be important subjects of research in ENT field.
Calcium ; Ion Channels ; Nociception ; Nociceptors ; Proteins ; Smell ; Thermoreceptors ; Transducers

Cervicogenic headache (CGH) is not universally accepted as terminology used to discuss headaches associated with disorders of the cervical spine. Sjaastad was the first to describe CGH that its definition and diagnosis relied entirely on clinical features. Pain is often triggered by irritation of nociceptors from structures in the cervical spine, and so diagnostic criteria of CGH have been established with agreement that these headaches start in the neck or occipital region and are associated with tenderness of cervical paraspinal tissues. Past history and clinical features are important to detect and diagnose the disease because the significance of radiological findings and advanced diagnostic testing is unclear. Gunn's intramuscular stimulation (IMS) is a treatment modality of CGH upon radiculopathic model. We tried IMS for treatment of 3 patients with CGH. After IMS, the patients were well respond the therapy and the results were satisfactory. Therefore we recommend the IMS for the treatment of CGH.
Diagnosis ; Diagnostic Tests, Routine ; Headache ; Humans ; Neck ; Nociceptors ; Post-Traumatic Headache* ; Spine

Opioids profoundly inhibit evoked discharges of spinal nociceptive neurons, thereby inhibiting the transmission of pain. Intrathecal administration of opioids using implantable continuous infusion systems is an effective method of pain relief when other treatments have failed, as well as for patients with adequate analgesia on high dose therapy that produces unacceptable side effects. We report two cases of intrathecal pump implantation performed in patients suffering from intractable chronic pain. A test dose of 3 mg morphine was injected into the epidural space. No side effects were noted and patients experienced considerable pain relief. Implantation was performed one day after the test. The initial intrathecal morphine delivery dose was half of the equivalent dose of daily oral intake opioids and the infusion rate was increased gradually under close observation for opioid side effects. Two days post-implantation, both patients were discharged without any complications.
Analgesia ; Analgesics, Opioid ; Chronic Pain ; Epidural Space ; Humans ; Infusion Pumps ; Morphine ; Nociceptors ; Stress, Psychological

Inflammation is one of the main causes of pathologic pain. Knowledge of the molecular links between inflammatory signals and pain-mediating neuronal signals is essential for understanding the mechanisms behind pain exacerbation. Some inflammatory mediators directly modulate the excitability of pain-mediating neurons by contacting the receptor molecules expressed in those neurons. For decades, many discoveries have accumulated regarding intraneuronal signals from receptor activation through electrical depolarization for bradykinin, a major inflammatory mediator that is able to both excite and sensitize pain-mediating nociceptor neurons. Here, we focus on the final effectors of depolarization, the neuronal ion channels, whose functionalities are specifically affected by bradykinin stimulation. Particular G-protein coupled signaling cascades specialized for each specific depolarizer ion channels are summarized. Some of these ion channels not only serve as downstream effectors but also play critical roles in relaying specific pain modalities such as thermal or mechanical pain. Accordingly, specific pain phenotypes altered by bradykinin stimulation are also discussed. Some members of the effector ion channels are both activated and sensitized by bradykinin-induced neuronal signaling, while others only sensitized or inhibited, which are also introduced. The present overview of the effect of bradykinin on nociceptor neuronal excitability at the molecular level may contribute to better understanding of an important aspect of inflammatory pain and help future design of further research on the components involved and pain modulating strategies.
Bradykinin* ; GTP-Binding Proteins ; Inflammation ; Ion Channels ; Neurons ; Nociceptors* ; Pain Perception* ; Phenotype

The purpose of present study was to compare the effects of somatostatin (SOM) and morphine (Mor) on the responses of wide dynamic range (WDR) cells to peripheral noxious stimulation. Single neuronal activity was recorded with a carbon-filament electrode at the lumbosacral enlargement of cat spinal cord. After identifying WDR cells, their responses to peripheral noxious mechanical or thermal stimuli were characterized and the effects of SOM and Mor, applied either iontophoretically or intrathecally, were studied. In most cells SOM and Mor suppressed noxious stimulus-evoked WDR neuronal activity, though a few WDR neurons showed no change or were excited by SOM and Mor. Systemically applied naloxone, a non-specific opioid antagonist, always reversed the Mor induced suppression of neuronal activity evoked by noxious mechanical stimuli, but did not always reverse the suppression of neuronal activity elicited by SOM. The suppressive effect of Mor on thermal stimulus-evoked neuronal activity was partially reversed by naloxone, while that of SOM were not reversed at all. The above results suggest that both Mor and SOM exert an inhibitory effect on thermal and mechanical stimulus-evoked WDR neuronal activity in cat spinal dorsal horn, but the mechanisms are dependent upon the functional populations of dorsal horn nociceptive neurons.
Animals ; Cats* ; Electrodes ; Horns* ; Hot Temperature* ; Morphine* ; Naloxone ; Neurons ; Nociceptors ; Somatostatin* ; Spinal Cord

BACKGROUND: This study was designed to investigate the correlation between pain and non-pain sensation of the cutaneous nociceptors in healthy adults use 250 Hz and 5 Hz evoking neuroselective sinusoidal current to A delta and C-fiber separately. METHODS: Fifty healthy adult volunteers who have no history of neurological illness were examined. Twenty-five of them were male, and twenty-five were female. Their ages ranged from 20 to 46 years, with a mean equal to 29.5 years old. The thresholds for both current perception and nociceptive perception were measured bilaterally in volar aspect of wrist using a Neurometer CPT/C (Quantitative Sensory Nerve Testing Device). The manual mode for current perception threshold and the staircase method for nociceptive current perception threshold was performed individually. RESULTS: The mean values of the threshold for perception evoked by 250 Hz were 0.30 mA in left and 0.31 mA in right, 0.17 mA in left and 0.14 mA in right at 5 Hz respectively. The mean values of the nociception threshold were 0.52 mA in both site at 250 Hz and from 0.35 mA to 0.32 mA at 5 Hz (Table 1). There were no differences between left and right wrist (Fig. 1). Also a significant positive correlation between current perception and nociception thresholds was found (p<0.05) (Fig. 2, 3). There appeared to be different between genders in perception threshold evoked by 250 Hz and nociception threshold evoked by 5 Hz in left (p<0.05) (Table 2). CONCLUSIONS: There exists a meaningful correlation between both sensations of non-pain and pain perception thresholds obtained from all subjects. The measurement of the current perception threshold is considered to be a unique and valuable resource in evaluation of patient with neurologic condition, as well as in serial evaluation of patient to assess the outcome of therapeutic intervention.
Adult* ; Female ; Humans ; Male ; Nociception* ; Nociceptors ; Pain Perception ; Sensation ; Volunteers ; Wrist

AIMTo research the influence of noxious stimuli on the electric activities of pain-related neurons in several subnuclei of Amygdaloid Nucleus in rats.

METHODSTrains of the electric impulses applied to the sciatic nerve were used as noxious stimuli. The discharges of neurons were channeled off by glass microelectrode.

RESULTSPain-related neurons existed in several subnuclei of Amygdaloid Nucleus. When the noxious stimuli were administered the frequency of discharges of pain-excited neurons (PEN) was increased while the frequency of pain-inhibited neurons (PIN) was decreased to the lowest level. The electric activities of PEN and PIN were matched with each other. Intraperitoneal injection of morphine (10 mg/kg) antagonized the effects of noxious stimuli on the pain-related neurons.

CONCLUSIONSeveral subnuclei of Amygdaloid Nucleus play an essential role in perceiving, integrating and transmitting the pain impulses. They are a part of the central nervous system in which pain information is controlled and managed.

Amygdala ; physiology ; Animals ; Electrophysiology ; Neurons ; physiology ; Nociceptors ; physiology ; Rats ; Rats, Wistar

AIMTo explore the cerebral cortex mechanism of visceral nociceptive sensation and its characteristics on the cell level, we investigated the membrane electrical properties of 176 stimulus-relative neurons of greater splanchnic nerve (GSN) in anterior cingulate gyrus (ACG) of 20 adult healthy cats.

METHODSWe used intracellular recording techniques of glass microelectrode and injected polarizing current into the neurons in ACG.

RESULTSAmong 176 neurons, 148 were visceral nociceptive neurons (VNNs) and 28 non-visceral nociceptive neurons (NVNNs). The membrane resistance (Rm), time constant (tau), membrane capacity (Cm), and the I-V curve of both VNNs and NVNNs in ACG were significantly different. The discharge frequency and amplitude of both VNNs and NVNNs produced by injecting depolarized current were different, too.

CONCLUSIONThe results suggest that structure of cell membrane, volume of the soma, and other aspects of morphology between VNNs and NVNNs in ACG may have significant differences. The results also might provide progressively experimental evidence for specific theory of pain sensation.

Animals ; Cats ; Gyrus Cinguli ; cytology ; physiology ; Membrane Potentials ; Nociceptors ; physiology ; Splanchnic Nerves ; physiology ; Visceral Afferents ; physiology

OBJECTIVETo study on mechanisms of acupuncture in relieving visceral pain.

METHODSIn SD rats CRD was used as noxious visceral stimuli. Activities of spinal dorsal horn wide dynamic (WDR) neurons of L1-L13 were recorded by extracellular microelectrode technique. Acupuncture was given at ipsi-lateral and contra-lateral Zusanli (ST 36) of the same segmental innervation of rectum and colon.

RESULTSVisceral noxious afferent could significantly activate spinal dorsal horn convergent neurons, and mechanical stimulation of contra-lateral body surface and hand acupuncture at Zusanli (ST 36) could inhibit this noxious response. When the spinal cord was acutely blocked, the inhibiting CRD effect of needling CRD effect of needling contra-lateral Zusanli (ST 36) completely disappeared.

CONCLUSIONAcupuncture and visceral noxious afferent signals converge and interact each other in spinal level, and acupuncture at acupoint can inhibit the spinal dorsal horn neuron respon se activated by visceral noxious afferent and this action needs the participation of the center above the spinal cord.

Animals ; Colon ; innervation ; Nociceptors ; Posterior Horn Cells ; Rats, Sprague-Dawley ; Rectum ; Spinal Cord