• Journal of Korean Neurosurgical Society
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• v.39 no.1
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• pp.52-57
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• 2006

Objective : It has been suggested that the occurrence of persistent pain signal during the early postnatal period may alter an individual's response to pain later in life. The aim of this study is to assess whether neonatal nerve injury resulted in long-lasting consequences on nociceptive system in the rat. Methods : We examined whether neuropathic pain behaviors and the changes of spinal neuropeptides [SP, CGRP, VIP and VIP] induced by peripheral nerve injury within 1 day after birth [Neonate group] were different from those at 8 weeks after birth [Mature group]. Results : The Neonate group showed more robust and long-lasting pain behaviors than the Mature group. Immunohistochemical findings demonstrated that spinal SP- & CGRP-immunoreactivities[ir] of the ipsilateral to the contralateral side increased in the Neonate group, whereas those decreased in the Mature group. In addition, increase in spinal VIP- & NPY-ir of the ipsilateral to the contralateral side was more robust in the Mature group than in the Neonate group. Conclusion : These results suggest that peripheral nerve injury in the early postnatal period may result in long-lasting and potentially detrimental alterations in nociceptive pathways.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.365-373
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• 1999

Somatostatin (SOM) is one of the major neuropeptides in dorsal root ganglion cells, but its role in spinal nociceptive process has not been well known. In present study we aimed to investigate the effect of SOM on the response of dorsal horn neurons to the various types of peripheral nociceptive stimuli in anesthetized cats. Using carbon-filament microelectrode, the single cell activities of wide dynamic range neurons were recorded from the lumbosacral enlargement after noxious mechanical (squeeze), thermal (radiant heat lamp) and cold (dry ice) stimulation to the receptive field. Sciatic nerve was stimulated electrically to evoke $A\;{\delta}-$ and C-nociceptive responses. SOM analogue, octreotide $(10\;{\mu}g/kg),$ was applied intravenously and the results were compared with those of morphine (2 mg/kg, MOR). Systemic SOM decreased the cellular responses to the noxious heat and the mechanical stimulation, but increased those to the cold stimulation. In the responses to the electric stimuli of sciatic nerve, $A\;{\delta}-nociceptive$ response was increased by SOM, while C-nociceptive response was decreased. On the other hand, MOR inhibited the dorsal horn cell responses to all the noxious stimuli. From the above results, it is concluded that SOM suppresses the transmission of nociceptive heat and mechanical stimuli, especially via C-fiber, while it facilitates those of nociceptive cold stimuli via $A\;{\delta}-fiber$.

• Korean Journal of Acupuncture
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• v.38 no.2
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• pp.75-99
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• 2021

Objectives : The purpose of this study is to analyze animal behavioral changes and related neurobiological mechanisms in recent studies using animal models with pain and depression. Methods : We conducted database search in Pubmed, NDSL, and EMBASE up to January 2021. Included studies were classified as depression-like behavior observed in pain model, pain-like behavior observed in depression model, and pain and depression comorbidity model. The results of pain- and depression-like behaviors, the changes of neurobiological mechanisms, and the treatment methods such as drugs, natural substance-derived chemicals, or acupuncture were analyzed. Results : We included 124 studies (81 studies in depression-like behavior observed in pain model, 19 studies in pain-like behavior observed in depression model, and 24 studies in pain and depression comorbidity model). Pain and depression comorbidity animal models were induced using various methods by drugs or surgery. Von frey test, a method for evaluating mechanical allodynia was the most commonly used for measuring pain-like behavior and the forced swimming test was the most commonly used for measuring depression-likes behavior. The changes of neurobiological factors, such as decrease of 5-hydroxytryptamine and increase of oxidative stress and pro-inflammation cytokines were generally changed in the frontal cortex, hippocampus, thalamus, and spinal cord in all types of models. For treating pain and depression-like behaviors, various types of drugs such as antidepressant, tranquilizer, analgesic, and natural substance-derived chemicals were used. Acupuncture treatment was used in 4 studies. Conclusions : In the future, more diverse studies on the combined model of pain and depression need to be conducted. In addition, it is necessary to establish a mechanistic basis for the development of various treatments by identifying the common mechanisms of pain and depression.