Publications by authors named "Lieju Liu"

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Exposure to PM2.5 has become one of the most important factors affecting public health in the world. Both clinical and research studies have suggested that PM2.

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Activation of cannabinoid receptor type 1 on presynaptic neurons is postulated to suppress neurotransmission by decreasing Ca(2+) influx through high voltage-gated Ca(2+) channels. However, recent studies suggest that cannabinoids which activate cannabinoid receptor type 1 can increase neurotransmitter release by enhancing Ca(2+) influx in vitro. The aim of the present study was to investigate the modulation of intracellular Ca(2+) concentration by the cannabinoid receptor type 1 agonist anandamide, and its underlying mechanisms.

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Vertebrobasilar insufficiency (VBI) presents complex varied clinical symptoms, including vertigo and hearing loss. Little is known, however, about how Ca(2+)-activated K(+) channel attributes to the medial vestibular nucleus (MVN) neural activity in VBI. To address this issue, we performed whole-cell patch clamp and quantitative polymerase chain reaction (qPCR) to examine the effects of hypoxia on neural activity and the changes of the large conductance Ca(2+) activated K(+) channels (BKCa channels) in the MVN neurons in brain slices of male C57BL/6 mice.

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Previously we observed that capsaicin, a transient receptor potential vanilloid 1 (TRPV1) receptor activator, inhibited transient potassium current (IA) in capsaicin-sensitive and capsaicin-insensitive trigeminal ganglion (TG) neurons from rats. It suggested that the inhibitory effects of capsaicin on IA have two different mechanisms: TRPV1-dependent and TRPV1-independent pathways. The main purpose of this study is to further investigate the TRPV1-independent effects of capsaicin on voltage-gated potassium channels (VGPCs).

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Study Design: Painful behavior testing, whole-cell patch clamp recordings, and PCR analysis were served to test the influence of T-type Ca channels in spinal nerve-injured rats.

Objective: To determine the changes of T-type Ca channels in dorsal root ganglion (DRG) neurons of different sizes and the contribution to neuronal firing and painful behavior in neuropathic pain induced by nerve injury.

Summary Of Background Data: T-type and high-voltage-activated Ca channels play an important role in the transmission of nociceptive signals, especially in neuronal hyperexcitability in neuropathic pain.

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Intracellular second messengers play an important role in capsaicin- and analogous-induced sensitization and desensitization in pain. Fluorescence Ca²⁺ imaging, enzyme immunoassay and PKC assay kit were used to determine a novel mechanism of different Ca²⁺ dependency in the signal transduction of capsaicin-induced desensitization. On the average, capsaicin increased cAMP, cGMP concentration and SP release in bell-shaped concentration-dependent manner, with the maximal responses at concentrations around 1 μM, suggesting acute desensitization of TRPV1 receptor activation.

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Ca(2+)-calmodulin (CaM) dependent protein kinase II (CaMKII) is an important intracellular signal transduction pathway. CaMKII is rich in the primary sensory neurons and specifically presents in the small- and medium-sized neurons. It remains unclear about the modulation on the excitability of primary sensory neurons by Ca(2+)-CaM-CaMKII pathway.

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ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) enhances cognitive functions; however, the underlying molecular mechanism remains unclear. Compelling evidence suggests that the endocannabinoid/endovanilloid systems play a pivotal role in regulating cognitive function. Thus, to correlate the effect of DHA on cognitive performance with the expression of endocannabinoid and endovanilloid receptors, we supplemented the diet of rats with DHA and performed in vitro experiments that focused on the endocannabinoid/endovanilloid receptors.

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Although the inhibitory effect of cannabinoids on transient receptor potential vanilloid 1 (TRPV1) channel may explain the efficacy of peripheral cannabinoids in antihyperalgesia and antinociceptive actions, the mechanism for cannabinoid-induced inhibition of TRPV1 in primary sensory neurons is not understood. Therefore, we explored how WIN55,212-2 (WIN, a synthetic cannabinoid) inhibited TRPV1 in rat trigeminal ganglion neurons. A "bell"-shaped concentration-dependent curve was obtained from the effects of WIN on TRPV1 channel.

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The present study explored the effect of anisotonicity on action potential (AP) in cultured trigeminal ganglion (TG) neurons. We demonstrate that the number of evoked APs was increased by both hypo- and hypertonic treatment. Transient Receptor Potential Vanilloid 4 receptor (TRPV4) activator increased the number of APs, but only hypotonic-response was markedly blocked in TRPV4-/- mice.

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Voltage-gated sodium channels (VGSCs) are important channels which participate in many physiological functions. Whether VGSCs can be modulated by changes in osmolality in trigeminal ganglion (TG) neurons remains unknown. In this study, by using whole-cell patch clamp techniques, we tested the effects of hypo- and hypertonicity on VGSCs in cultured TG neurons.

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Voltage-gated calcium channels (VGCCs) participate in many important physiological functions. However whether VGCCs are modulated by changes of osmolarity and involved in anisotonicity-induced nociception is still unknown. For this reason by using whole-cell patch clamp techniques in rat and mouse trigeminal ganglion (TG) neurons we tested the effects of hypo- and hypertonicity on VGCCs.

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The present study aimed to investigate whether cannabinoids could modulate the response mediated by ATP receptor (P2X purinoceptor). Whole-cell patch-clamp recording was performed on cultured rat trigeminal ganglionic (TG) neurons. The majority of TG neurons were sensitive to ATP (67/75, 89.

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Two different mechanisms by which capsaicin blocks voltage-gated sodium channels (VGSCs) were found by using knockout mice for the transient receptor potential V1 (TRPV1(-/-)). Similar with cultured rat trigeminal ganglion (TG) neurons, the amplitude of tetrodotoxin-resistant (TTX-R) sodium current was reduced 85% by 1 muM capsaicin in capsaicin sensitive neurons, while only 6% was blocked in capsaicin insensitive neurons of TRPV1(+/+) mice. The selective effect of low concentration capsaicin on VGSCs was reversed in TRPV1(-/-) mice, which suggested that this effect was dependent on TRPV1 receptor.

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To investigate the effect of interleukin-1beta (IL-1beta) on I(A) and I(K) currents in cultured murine trigeminal ganglion (TG) neurons, whole-cell patch clamp technique was used to record the I(A) and I(K) currents before and after 20 ng/mL I(L)-1beta perfusion. Our results showed that 20 ng/mL IL-1beta inhibited I(A) currents (18.3 +/- 10.

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The effects of phorbol-12,13-dibuterate (PDBu) on total sodium current (I(Na)-total), tetrodotoxin-resistant sodium current (I(Na)-TTXr), 4-AP-sensitive potassium current (I(A)) and TEA-sensitive potassium current (I(K)) in trigeminal ganglion (TG) neurons were investigated. Whole-cell patch clamp techniques were used to record ion currents in cultured TG neurons of rats. Results revealed that 0.

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Changes in tonicity in the peripheral nervous system can activate nociceptors and produce pain. Under local inflammatory conditions the peripheral terminals of nociceptors are subject to deviations from isotonicity. Previously it was shown that several members of the TRP(V) family of ion channels are responsive to changes in tonicity.

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The different effects of capsaicin on I(A) and I(K) currents in pain-conduct neurons of trigeminal ganglia (TG) were investigated. In cultured TG neurons of rats, whole-cell patch clamp techniques were used to record the I(A) and I(K) before and after capsaicin perfused. Results revealed that 1 micromol/L capsaicin could inhibit the amplitude of I(A) by 48.

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The proinflammatory cytokine interleukin-1beta (IL-1beta) mediates inflammation and hyperalgesia, although the underlying mechanisms remain elusive. To better understand such molecular and cellular mechanisms, we investigated how IL-1beta modulates the total voltage-dependent sodium currents (INa) and its tetrodotoxin-resistant (TTX-R) component in capsaicin-sensitive trigeminal nociceptive neurons, both after a brief (5-min) and after a chronic exposure (24-h) of 20 ng/ml IL-1beta. A brief exposure led to a 28% specific (receptor-mediated) reduction of INa in these neurons, which were found to contain type I IL-1 receptors (IL-1RI+) on both their soma and nerve endings.

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This experiment aimed to investigate the effect of adrenergic system in the subnucleus commissuriu of nucleus solitrius tractus (CNTS) on renal nerve discharges. Norepinephrine (NE) was microinjected into the CNTS of rabbits and mean arterial blood pressure (MAP) and renal nerve discharges (FRND) were synchronously recorded. The results indicated that (1) microinjection of norepinephine into the CNTS of rabbit could significantly attenuate the frequency of renal nerve discharge, and at the same time decrease markedly the mean arterial pressure.

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To investigate the effects of WIN 55,212-2 on I(K) in cultured rat trigeminal ganglion (TG) neurons, whole-cell patch clamp techniques were used to record the I(K) before and after WIN 55,212-2 perfusion at different concentrations. 30 micromol/L WIN 55,212-2 markedly (35.7% +/- 7.

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Aim: To investigate the effect of capsaicin on IA and IK in cultured rat trigeminal ganglion (TG) neurons.

Methods: Whole-cell patch clamp technique was used to record the IA and IK before and after capsaicin perfusion at different concentrations.

Results: In capsaicin-sensitive (CS) neurons, capsaicin was shown to selectively inhibit IA in dose-dependent manner, the IC50 was 0.

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