Articles: hyperalgesia.
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Anesthesia and analgesia · Nov 2017
Case ReportsCase Series of Successful Postoperative Pain Management in Buprenorphine Maintenance Therapy Patients.
Buprenorphine maintenance therapy patients frequently have severe postoperative pain due to buprenorphine-induced hyperalgesia and provider use of opioids with limited efficacy in the presence of buprenorphine. The authors report good-to-excellent pain management in 4 obstetric patients using nonopioid analgesics, regional anesthesia, continuation of buprenorphine, and use of opioids with high μ receptor affinity.
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Neurons in the rostral ventromedial medulla (RVM) project to the spinal cord and are involved in descending modulation of pain. Several studies have shown that activation of neurokinin-1 (NK-1) receptors in the RVM produces hyperalgesia, although the underlying mechanisms are not clear. In parallel studies, we compared behavioral measures of hyperalgesia to electrophysiological responses of nociceptive dorsal horn neurons produced by activation of NK-1 receptors in the RVM. ⋯ NEW & NOTEWORTHY It is known that activation of neurokinin-1 (NK-1) receptors in the rostral ventromedial medulla (RVM), a main output area for descending modulation of pain, produces hyperalgesia. Here we show that activation of NK-1 receptors produces hyperalgesia by sensitizing nociceptive dorsal horn neurons. Targeting this pathway at its origin or in the spinal cord may be an effective approach for pain management.
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Biomed. Pharmacother. · Nov 2017
Comparative StudyThe flavonoid 6-methoxyflavone allays cisplatin-induced neuropathic allodynia and hypoalgesia.
Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose limiting side-effect of several commonly used chemotherapeutic agents (such as cisplatin) that profoundly impairs patient quality of life. Unfortunately, neither prophylactic strategies nor symptomatic treatments have proven useful in this condition. Flavonoids are found ubiquitously in fruits and vegetables and exert a multiplicity of beneficial effects. ⋯ However, these antinociceptive actions were associated with motor impairment exemplified by a significant decrease in rotarod endurance latency and a deficit in the uniformity of step alternation. In contrast, 6-MF was devoid of these adverse side-effects. These findings suggested that 6-MF afforded desirable neuropathic pain alleviating effects in CIPN and it was devoid of gabapentin-like unwanted motor side-effects.
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Paclitaxel, a chemotherapy drug for solid tumors, induces peripheral painful neuropathy. Bee venom acupuncture (BVA) has been reported to have potent analgesic effects, which are known to be mediated by activation of spinal α-adrenergic receptor. Here, we investigated the effect of BVA on mechanical hyperalgesia and spinal neuronal hyperexcitation induced by paclitaxel. ⋯ Both melittin (0.5 mg/kg, ST36) and phospholipase A2 (0.12 mg/kg, ST36) were shown to play an important part in this analgesic effect of the BVA, as they significantly attenuated the pain. Intrathecal pretreatment with the α₂-adrenergic receptor antagonist (idazoxan, 50 µg), but not α₁-adrenergic receptor antagonist (prazosin, 30 µg), blocked the analgesic effect of BVA. These results suggest that BVA has potent suppressive effects against paclitaxel-induced neuropathic pain, which were mediated by spinal α₂-adrenergic receptor.
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Following tissue injury, phosphorylation of p38 MAPK in the primary afferent neurons drives sensitization of peripheral nerve. Dexmedetomidine extends the duration of reginal analgesia by local anesthetics. The effect of regional analgesia on the peripheral nerve sensitization is not known. ⋯ Levobupivacaine without dexmedetomidine could not inhibit p38 MAPK phosphorylation in the DRG completely. However, Levobupivacaine and dexmedetomidine completely inhibited p38 MAPK phosphorylation, and reduced macrophage accumulation and TNF-α amount in the plantar tissue. Inhibition of p38 MAPK phosphorylation via TNF-α suggests dexmedetomidine has a peripheral mechanism of anti-inflammatory action when used asan adjunct to local anesthetics, and provides a molecular basis for the prevention of peripheral sensitization following surgery.