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.
Dear editor, P-glycoprotein （P-gp, also known as ATP-binding cassette transport sub-family B member 1, ABCB1） is a potent ATP-dependent efflux pump for a wide variety of drugs. Although studies of its substrates are abundant [ 1, 2], and ABCB1 is a well-conserved gene, there is increasing evi- dence that its polymorphisms affect substrate specificity [3]. A previous study reported that the synonymous single nucleotide polymorphism （SNP） C3435T （rs1045642） affects the timing of co-translational folding and insertionof P-gp into the membrane,
Protein kinase D （PKD） is an evolutionarily-conserved family of protein kinases. It has structural, regulatory, and enzymatic properties quite different from the PKC family. Many stimuli induce PKD signaling, including G-protein-coupled receptor agonists and growth factors. PKD1 is the most studied member of the family. It functions during cell proliferation, differentiation, secretion, cardiac hypertrophy, immune regulation, angiogenesis, and cancer. Previously, we found that PKD1 is also critically involved in pain modulation. Since then, a series of studies performed in our lab and by other groups have shown that PKDs also participate in other processes in the nervous system including neuronal polarity establishment, neuroprotection, and learning. Here, we discuss the connections between PKD structure, enzyme function, and localization, and summarize the recent findings on the roles of PKD-mediated signaling in the nervous system.
