α7 烟碱型乙酰胆碱受体正变构调节剂对脂多糖诱导的炎症痛模型小鼠海马中 BDNF、NKCC1 和 KCC2 表达的影响。
Effects of α7 Nicotinic Acetylcholine Receptor Positive Allosteric Modulator on BDNF, NKCC1 and KCC2 Expression in the Hippocampus following Lipopolysaccharide-Induced Allodynia and Hyperalgesia in a Mouse Model of Inflammatory Pain.
机构信息
Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings SD 57007, United States.
Department of Pharmacology and Therapeutics, University of Florida, Gainesville FL 32610, United States.
出版信息
CNS Neurol Disord Drug Targets. 2021;20(4):366-377. doi: 10.2174/1871527319666201230102616.
BACKGROUND & OBJECTIVES: Hyperalgesia and allodynia are frequent symptoms of inflammatory pain. Neuronal excitability induced by the Brain-Derived Neurotrophic Factor (BDNF)-tyrosine receptor kinase B (TrkB) cascade has a role in the modulation of inflammatory pain. The effects of 3a,4,5,9b-tetrahydro-4-(1-naphthalenyl)-3H-cyclopentan[c]quinoline-8-sulfonamide (TQS), an α7 nicotinic Acetylcholine Receptor Positive Allosteric Modulator (nAChR PAM), on hippocampal BDNF, cation-chloride cotransporters, NKCC1 and KCC2, expression in inflammatory pain are not known. The objective of the study was to determine the effects of TQS on BDNF, NKCC1, and KCC2 expression in the hippocampus following lipopolysaccharide (LPS)-induced allodynia and hyperalgesia in a mouse model of inflammatory pain.
METHODS
Mice were treated with TQS followed by LPS (1 mg/kg, ip) administration. The effects of TQS on mRNA and BDNF in the hippocampus were examined using qRT-PCR and Western blot, respectively. Immunoreactivity of BDNF, NKCC1, and KCC2 in the hippocampus was measured after LPS administration using immunofluorescence assay. Allodynia and hyperalgesia were determined using von Frey filaments and hot plate, respectively.
RESULTS
The LPS (1 mg/kg) upregulates mRNA of BDNF and downregulates mRNA of KCC2 in the hippocampus and pretreatment of TQS (4 mg/kg) reversed the effects induced by LPS. In addition, the TQS decreased LPS-induced upregulation of BDNF and p-NKCC1 immunoreactivity in the dentate gyrus and CA1 region of the hippocampus. BDNF receptor (TrkB) antagonist, ANA12 (0.50 mg/kg), and NKCC1 inhibitor bumetanide (30 mg/kg) reduced LPS-induced allodynia and hyperalgesia. Blockade of TrkB with ANA12 (0.25 mg/kg) enhanced the effects of TQS (1 mg/kg) against LPS-induced allodynia and hyperalgesia. Similarly, bumetanide (10 mg/kg) enhanced the effects of TQS (1 mg/kg) against allodynia and hyperalgesia.
CONCLUSION
These results suggest that antinociceptive effects of α7 nAChR PAM are associated with downregulation of hippocampal BDNF and p-NKCC1 and upregulation of KCC2 in a mouse model of inflammatory pain.
背景与目的
痛觉过敏和感觉异常是炎症性疼痛的常见症状。脑源性神经营养因子（BDNF）-酪氨酸受体激酶 B（TrkB）级联诱导的神经元兴奋性在调节炎症性疼痛中起作用。3a、4、5、9b-四氢-4-（1-萘基）-3H-环戊烷[c]喹啉-8-磺酰胺（TQS），一种α7 烟碱型乙酰胆碱受体正变构调节剂（nAChR PAM），对炎症性疼痛中海马 BDNF、阳离子-氯离子共转运蛋白 NKCC1 和 KCC2 表达的影响尚不清楚。本研究的目的是确定 TQS 对脂多糖（LPS）诱导的炎症性疼痛小鼠模型中海马 BDNF、NKCC1 和 KCC2 表达的影响。
方法
小鼠用 TQS 预处理后给予 LPS（1mg/kg，ip）。采用 qRT-PCR 和 Western blot 分别检测 TQS 对海马组织中 BDNF mRNA 和蛋白的影响。用免疫荧光法检测 LPS 给药后海马组织中 BDNF、NKCC1 和 KCC2 的免疫反应性。用 von Frey 细丝和热板分别测定痛觉过敏和痛觉。
结果
LPS（1mg/kg）上调了海马组织中 BDNF 的 mRNA，下调了 KCC2 的 mRNA，TQS（4mg/kg）预处理逆转了 LPS 诱导的作用。此外，TQS 降低了 LPS 诱导的海马齿状回和 CA1 区 BDNF 和 p-NKCC1 免疫反应性的上调。BDNF 受体（TrkB）拮抗剂 ANA12（0.50mg/kg）和 NKCC1 抑制剂布美他尼（30mg/kg）减轻了 LPS 诱导的痛觉过敏和痛觉。用 ANA12（0.25mg/kg）阻断 TrkB 增强了 TQS（1mg/kg）对 LPS 诱导的痛觉过敏和痛觉的作用。同样，布美他尼（10mg/kg）增强了 TQS（1mg/kg）对痛觉过敏和痛觉的作用。
结论
这些结果表明，在炎症性疼痛小鼠模型中，α7 nAChR PAM 的抗伤害作用与下调海马 BDNF 和 p-NKCC1 以及上调 KCC2 有关。
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