Repetitive Treatment with Diluted Bee Venom Reduces Neuropathic Pain Via Potentiation of Locus Coeruleus Noradrenergic Neuronal Activity and Modulation of Spinal NR1 Phosphorylation in Rats
– Source: Journal of Pain, Feb 2012
[Note: Neuropathic pain results from a pinched, inflamed, swollen or injured nerve or nerves. An ancient though cruder pain control strategy involves application of ‘injection’ by bee stings to painful joints. See demonstration video/explanation . Stings can be life-threatening to some people who are allergic, so never try this at home!]
We previously demonstrated that a single injection of diluted bee venom (DBV) temporarily alleviates thermal hyperalgesia [pain caused by heat or cold], but not mechanical allodynia [caused by an injury], in neuropathic rats.
The present study was designed to determine whether repetitive injection of diluted bee venom produces more potent analgesic effects on neuropathy-induced nociception and whether those effects are associated with increased neuronal activity in the locus coeruleus (LC) and with the suppression of spinal NMDA receptor NR1 subunit phosphorylation (pNR1). [Spinal NMDA receptors are involved in pain signal processing.]
Diluted bee venom (.25 mg/kg) was administered subcutaneously twice a day for 2 weeks beginning on day 15 post-chronic constrictive injury surgery.
Pain responses were examined and potential changes in LC Fos expression and spinal pNR1 expression were determined.
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Repetitive DBV administration significantly reduced mechanical allodynia, as well as thermal hyperalgesia.
The activity of LC noradrenergic neurons was increased and spinal pNR1 expression was significantly suppressed by repetitive DBV as compared with those of vehicle or single DBV injection.
These suppressive effects of repetitive DBV on neuropathic pain and spinal pNR1 were prevented by intrathecal pretreatment of idazoxan, an alpha-2 adrenoceptor antagonist.
These results indicate that repetitive DBV produces potent analgesic effects on neuropathic pain and this is associated with the activation of the LC noradrenergic system and with a reduction in spinal pNR1.
The results of current study demonstrate that repetitive administration of DBV significantly suppresses neuropathic pain.
Furthermore, this study provides mechanistic information that repetitive treatment of DBV can produce more potent analgesic effect than single DBV treatment, indicating a potential novel strategy for the management of chronic pain.
Source: The Journal of Pain, Feb 2012; vol 13(2), pp. 155-166. Kang S, Roh D, Yoon S, Moon J, Kim H, Lee H, Beitz AJ, Lee J. Seoul National University, South Korea; University of Texas MD Anderson Cancer Center, Houston, USA; Chungnam National University Medical School, Daejeon, South Korea; Kung Hee University, Seoul, South Korea; University of Minnesota, St. Paul, Minnesota, USA. [Email: JHL1101@snu.ac.kr ]