Anti-allodynic effect of 2-(aminomethyl)adamantane-1-carboxylic acid in a rat model of neuropathic pain: A mechanism dependent on CaV2.2 channel inhibition
摘要:
Neuropathic pain is a serious physical disabling condition resulting from lesion or dysfunction of the peripheral sensory nervous system. Despite the fact that the mechanisms underlying neuropathic pain are poorly understood, the involvement of voltage-gated calcium (Ca-V) channels in its pathophysiology has justified the use of drugs that bind the Ca-V channel alpha(2)delta auxiliary subunit, such as gabapentin (GBP), to attain analgesic and anti-allodynic effects in models involving neuronal sensitization and nerve injury. GBP binding to alpha(2)delta inhibits nerve injury-induced trafficking of the alpha(1) pore forming subunits of Ca-V channels, particularly of the N-type, from the cytoplasm to the plasma membrane of pre-synaptic terminals in dorsal root ganglion neurons and dorsal horn spinal neurons. In the search for alternative forms of treatment, in this study we describe the synthesis and pharmacological profile of a GABA derivative, 2-aminoadamantane-1-carboxylic acid (GZ4), which displays a close structure-activity relationship with GBP. Behavioral assessment using von Frey filament stimuli showed that GZ4 treatment reverted mechanical allodynia/hyperalgesia in an animal model of spinal nerve ligation-induced neuropathic pain. In addition, using the patch clamp technique we show that GZ4 treatment significantly decreased whole-cell currents through N-type Ca-V channels heterologously expressed in HEK-293 cells. Interestingly, the behavioral and electrophysiological time course of GZ4 actions reflects that its mechanism of action is similar but not identical to that of GBP. While GBP actions require at least 24 h and imply uptake of the drug, which suggests that the drug acts mainly intracellularly affecting channels trafficking to the plasma membrane, the faster time course (1-3 h) of GZ4 effects suggests also a direct inhibition of Ca2+ currents acting on cell surface channels. (C) 2014 Elsevier Ltd. All rights reserved.
The conformation of bicyclo[3.3.1]nonane-3α,7α-dicarboxylic acid and its dimethyl ester has been studied by comparing 1H NMR and 13C NMR spectra of these compounds with those of some model 3,7-disubstituted bicyclo[3.3.1]nonanes, fixed in a single conformation by the use of adamantane as an integrated holding group or by means of suitable substitution. It is shown that the dicarboxylic acid and its
通过比较这些化合物的1 H NMR和13 C NMR谱图与某些模型的3,7-二取代双环[3.3]谱图,研究了双环[3.3.1]壬烷-3α,7α-二羧酸及其二甲酯的构象。.1]壬烷,通过使用金刚烷作为一个整体的保留基团或通过适当的取代固定在一个构象中。结果表明,二羧酸及其二甲基酯主要以两个快速相互转化(相同)的椅形结构存在,并且环明显扁平。双人船构型的人口似乎很少。
ARMAREGO W. L. F.; TUCKER P. G., AUSTRAL. . CHEM., 1979, 32, NO 8, 1805-1817