M-type potassium current （IM） was initially isolated from sympathetic neurons in 1980 and named as it was inhibited by muscarine. In 1998, the molecular identity of M-current was revealed to be heterotetramers of KCNQ2 and KCNQ3 subunits, whose mutations cause neonatal epilepsy. Reduction of voltage-gated KCNQ2/3 K＋ channel （M-channel） activity leads to neuronal byperexcitability that defines the fundamental mechanism of neurological disorders such as epilepsy and pain. Thus, suppression of neuronal hyperexcitability by activation of KCNQ2/3 channels serves the basis for development of the channel openers for treatment of epilepsy and pain. The well-known KCNQ opener is retigabine （Potiga） that was approved by FDA as an antiepileptic drug in 2011. Recent studies also provide evidence that KCNQ2/3 channel openers are effective in animal models of bipolar disorder, anxiety and schizophrenia, whereas KCNQ2/3 inhibitors, on the other hand, are indicated for improvement of learning and memory in animal models. We recently designed and validated a novel series of pyrazolo [1,5-a]pyrimidin-7（4H）-ones （PPOs） that selectively activate KCNQ2/3 and show antiepileptic and analgesic activity in vivo. Up to date, all the progress made enforces the view that targeting voltage-gated KCNQ/M-channel may provide therapeutic potential for treatment of neuropsychiatric disorders.
Neurosteroids are synthesized in the nervous system from cholesterol or steroidal precursors imported from peripheral sources. These compounds are important allosteric modulators of γ-aminobutyric acid A receptors （GABAARs）, which play a vital role in pain modulation in the lateral thalamus, a main gate where somatosensory information enters the cerebral cortex. Using high-perfor mance liquid chromatography/tandem mass spectrometry, we found increased levels of neurosteroids （pregnenolone, progesterone, deoxycorticosterone, allopregnanolone, and tetrahydrodeoxycorticosterone） in the chronic stage of neuropathic pain （28 days after spared nerve injury） in rats.The expression of the translocator protein TSPO, the upstream steroidogenesis rate-limiting enzyme, increased at the same time. In vivo stereotaxic microinjection of neurosteroids or the TSPO activator AC-5216 into the lateral thalamus （AP -3.0 mm, ML 4-3.0 mm, DV 6.0 mm） alleviated the mechanical allodynia in neuropathic pain, while the TSPO inhibitor PK 11195 exacerbated it. The analgesic effects of AC-5216 and neurosteroids were sig- nificantly attenuated by the GABAAR antagonist bicuculline. These results suggested that elevated neurosteroids in the lateral thalamus play a protective role in the chronic stage of neuropathic pain.
In all six members of TRPV channel subfamily,there is an ankyrin repeat domain(ARD)in their intracellular N-termini.Ankyrin(ANK)repeat,a common motif with typi-cally 33 residues in each repeat,is primarily involved in protein-protein interactions.Despite the sequence similarity among the ARDs of TRPV channels,the struc-ture of TRPV3-ARD,however,remains unknown.Here,we report the crystal structure of TRPV3-ARD solved at 1.95Åresolution,which reveals six-ankyrin repeats.While overall structure of TRPV3-ARD is similar to ARDs from other members of TRPV subfamily;it,however,features a noticeable fi nger 3 loop that bends over and is stabilized by a network of hydrogen bonds and hydrophobic pack-ing,instead of being fl exible as seen in known TRPV-ARD structures.Electrophysiological recordings demonstrated that mutating key residues R225,R226,Q255,and F249 of fi nger 3 loop altered the channel activities and pharmacol-ogy.Taken all together,our findings show that TRPV3-ARD with characteristic fi nger 3 loop likely plays an im-portant role in channel function and pharmacology.
Di-Jing ShiSheng YeXu CaoRongguang ZhangKeWei Wang
Acupuncture, as a healing art in traditional Chinese medicine, has been widely used to treat various diseases. In the history of acupuncture anesthesia, in the past decades, mechanisms of acupuncture analgesia has been widely investigated, and in recent years, acupuncture protection on organ functions has attracted great interest. This review summarized the research progress on mechanisms of acupuncture for analgesia and its protection against organ function injury in anesthesia, and its perspective of analgesia, immunomodulation, neuroendocrine regulation and multiple organ protection. The current evidence supports that acupuncture analgesia and its organ protection in anesthesia is associated with the integration of neuroendocrine-immune networks in the level of neurotransmitters, cytokines, hormones, neuronal ensembles,lymphocytes, and endocrine cells. Although the mechanisms of acupuncture analgesia and its organ protection are still not completely understood, basic as well as clinic researches on the mechanisms and applications of acupuncture and related techniques are being carried out.
