Anti-Microbial Effect of AgBr-NP@CTMAB on Streptococcus Mutans and Assessment of Surface Roughness Hardness and Flexural Strength of PMMA.

Purpose: To investigate the inhibition of Streptococcus mutans (S.mutans) and its biofilm by AgBr-nanoparticles (NP) @CTMAB (cetyltrimethyl-ammonium bromide) and evaluate the changes in Polymethyl methacrylate (PMMA)'s surface roughness (Ra), microhardness, and flexural strength during prolonged immersion in AgBr-NP@CTMAB for application in the denture cleaning industry. Patients and Methods: The antibacterial activity of AgBr-NP@CTMAB against S.mutans was measured colony formation assay, OD600 and laser confocal microscopy. Changes in the specimens' values for surface roughness, microhardness, and flexural strength (MPa) were measured after immersion solutions for 180 or 360 days. Results: The AgBr-NP@CTMAB solution exhibited a robust antibacterial effect on planktonic S. mutans, with a minimum bactericidal concentration of 5 µg/mL. The 10 µg/mL AgBr-NP@CTMAB solution efficiently inhibited S. mutans biofilm formation. (2) No significant difference in surface roughness after immersion in AgBr-NP@CTMAB (10 µg/mL and 20 µg/mL) comparing with distilled water (P > 0.05) and Polident had significantly higher than distilled water (P < 0.05). There was a significant decrease in the surface hardness of the PMMA specimens that were immersed in the Polident compared with those in distilled water (P < 0.05). While, no significant differences in surface hardness after immersion in the AgBr-NP@CTMAB (P > 0.05). The result of flexural strength suggested that there was no statistically significant difference (P < 0.05) between AgBr-NP@CTMAB as well as Polident and water. Conclusion: AgBrNP@CTMAB can efficiently inhibit the growth of plankton S.mutans and biofilm formation, without affecting the flexural strength, microhardness, or surface roughness of PMMA. Therefore, AgBrNP@CTMAB holds promise as a new denture cleaning agent.

Molecular rotators anchored on a rod-like anionic coordination polymer adhered by charge-assisted hydrogen bonds.

On the basis of variable-temperature single-crystal X-ray diffraction, variable-temperature/frequency dielectric analysis, variable-temperature solid-state nuclear magnetic resonance spectroscopy, and molecular dynamics simulations, here we present a new model of crystalline supramolecular rotor (i-PrNHMe2)[CdBr3], where a conformationally flexible near-spherical (i-PrNHMe2)+ cation functions as a rotator and a rod-like anionic coordination polymer {[CdBr3]-}∞ acts as the stator, and the adhesion of them is realized by charge-assisted hydrogen bonds.

Potentiation of the lateral habenula-ventral tegmental area pathway underlines the susceptibility to depression in mice with chronic pain.

Chronic pain often develops severe mood changes such as depression. However, how chronic pain leads to depression remains elusive and the mechanisms determining individuals' responses to depression are largely unexplored. Here we found that depression-like behaviors could only be observed in 67.9% of mice with chronic neuropathic pain, leaving 32.1% of mice with depression resilience. We determined that the spike discharges of the ventral tegmental area (VTA)-projecting lateral habenula (LHb) glutamatergic (Glu) neurons were sequentially increased in sham, resilient and susceptible mice, which consequently inhibited VTA dopaminergic (DA) neurons through a LHbGlu-VTAGABA-VTADA circuit. Furthermore, the LHbGlu-VTADA excitatory inputs were dampened via GABAB receptors in a pre-synaptic manner. Regulation of LHb-VTA pathway largely affected the development of depressive symptoms caused by chronic pain. Our study thus identifies a pivotal role of the LHb-VTA pathway in coupling chronic pain with depression and highlights the activity-dependent contribution of LHbGlu-to-VTADA inhibition in depressive behavioral regulation.

Switching the memory behaviour from binary to ternary by triggering S62- relaxation in polysulfide-bearing zinc-organic complex molecular memories.

The use of crystalline metal-organic complexes with definite structures as multilevel memories can enable explicit structure-property correlations, which is significant for designing the next generation of memories. Here, four Zn-polysulfide complexes with different degrees of conjugation have been fabricated as memory devices. ZnS6(L)2-based memories (L = pyridine and 3-methylpyridine) can exhibit only bipolar binary memory performances, but ZnS6(L)-based memories (L = 2,2'-bipyridine and 1,10-phenanthroline) illustrate non-volatile ternary memory performances with high ON2/ON1/OFF ratios (104.22/102.27/1 and 104.85/102.58/1) and ternary yields (74% and 78%). Their ON1 states stem from the packing adjustments of organic ligands upon the injection of carriers, and the ON2 states are a result of the ring-to-chain relaxation of S62- anions. The lower conjugated degrees in ZnS6(L)2 result in less compact packing; consequently, the adjacent S62- rings are too long to trigger the S62- relaxation. The deep structure-property correlation in this work provides a new strategy for implementing multilevel memory by triggering polysulfide relaxation based on the conjugated degree regulation of organic ligands.

Synthetic Antibacterial Quaternary Phosphorus Salts Promote Methicillin-Resistant Staphylococcus aureus-Infected Wound Healing.

Background: Drug-resistant microbes pose a global health concern, requiring the urgent development of effective antibacterial agents and strategies in clinical practice. Therefore, there is an urgent need to explore novel antibacterial materials to effectively eliminate bacteria. The synthesis of quaternary phosphonium salt in haloargentate systems, wherein the phosphorus atom is represented in a cationic form, is a possible strategy for the development of antibacterial materials. Methods: Using (triphenyl)phosphonium-based quaternary phosphorus salts with different spacer lengths (n=2, 4, 6) as a template, we designed three kinds of quaternary phosphorus salts as effective antibacterial agents against drug-resistant bacteria. Results: The synthesized quaternary phosphorus salt of (1,4-DBTPP)Br2 effectively prevented the formation of the bacterial biofilms, and degraded bacterial membranes and cell walls by promoting the production of reactive oxygen species, which exhibited effective therapeutic effects in a rat model of a superficial wound infected with methicillin-resistant Staphylococcus aureus. Conclusion: The quaternary phosphorus salt (1,4-DBTPP)Br2 demonstrated hemocompatibility and low toxicity, revealing its potential in the treatment of clinical infections.

Embedding Azobenzol-Decorated Tetraphenylethylene into the Polymer Matrix to Implement a Ternary Memory Device with High Working Temperature/Humidity.

The development of new high-density memories that can work in harsh environments such as high temperature and humidity will be significant for some special occasions such as oil and geothermal industries. Herein, a facial strategy for implementing a ternary memory device with high working temperature/humidity was executed. In detail, an asymmetric aggregation-induced-emission active molecule (azobenzol-decorated tetraphenylethylene, i.e., TPE-Azo) was embedded into flexible poly(ethylene-alt-maleic anhydride) (PEM) to prepare a TPE-Azo@PEM composite, which served as an active layer to fabricate the FTO/TPE-Azo@PEM/Ag device. This device can demonstrate excellent ternary memory performances with a current ratio of 1:104.2:101.6 for "OFF", "ON1", and "ON2" states. Specially, it can exhibit good environmental endurance at high working temperature (350 °C) and humidity (RH = 90%). The ternary memory mechanism can be explained as the combination of aggregation-induced current/conductance and conformational change-induced charge transfer in the TPE-Azo molecule, which was verified by Kelvin probe force microscopy, UV-vis spectra, X-ray diffraction, and single-crystal structural analysis. This strategy can be used as a universal method for the construction of high-density multilevel memristors with good environmental tolerance.

Thermal-Responsive Polyoxometalate-Metalloviologen Hybrid: Reversible Intermolecular Three-Component Reaction and Temperature-Regulated Resistive Switching Behaviors.

The development of new-type memristors with special performance is of great interest. Herein, an inorganic-organic hybrid crystalline polyoxometalate (POM) with usual dynamic structures is reported and used as active material for fabricating memristor with unique temperature-regulated resistive switching behaviors. The hybrid POM not only exhibits tunable thermochromic properties, but also thermal-induced reversible aggregation and disaggregation reactions, leading to reversible structural transformations in SCSC fashion. Further, the memory device using the hybrid POM as active layer exhibits uncommon performance, which can keep resistive switching silent in the low temperature range of 30-150 °C, but show nonvolatile memory behavior in the high temperature range of 150-270 °C. Particularly, the silent and working states at three special temperatures (30, 150 and 270 °C) can be monitored by chromism. The correlation between structure and resistive switching property of the material has been discussed. The work demonstrates that crystalline inorganic-organic hybrid POMs are promising materials for making memristors with superior performance.

Synthesis, Antifungal Activity, and Cytotoxicity of AgBr-NP@CTMAB Hybrid and Its Application in PMMA.

OBJECTIVE: To synthesize and determine the antifungal activity of AgBr-nanoparticles (NP) @CTMAB (cetyltrimethyl-ammonium bromide) against Candida albicans (C. albicans) for use in the field of denture cleaning. METHODS: The morphology and structure of AgBr-NP@CTMAB were characterized by IR, UV-Vis, XRD and SEM. The antifungal potential of AgBr-NP@CTMAB against C. albicans was determined by colony formation assay and growth curve analysis. PMMA containing AgBr-NP@CTMAB was prepared, and the long-term antifungal efficacy was analyzed. The effect against C. albicans biofilm was analyzed by SEM and OD600 , and the color changes of the specimens were observed by stereomicroscopy after 1 week of incubation. Cytotoxicity to human oral gingival fibroblasts and oral mucosal epithelial cells was detected by Cell Counting Kit-8 (CCK-8) in vitro. RESULTS: The compound showed a good crystalline phase, the presence of AgBr nanoparticles and the hybridization of CTMAB+ with AgBr-NPs. AgBr-NP@CTMAB showed significant antifungal activity against C. albicans at concentrations of 10 µg/mL and 20 µg/mL. PMMA specimens containing AgBr-NP@CTMAB showed no long-term antifungal effect against C. albicans biofilm. The clearance rate of C. albicans attached to PMMA was 44.73% after soaking in 10 µg/mL AgBr-NP@CTMAB solution for 30 min and 91.35% for 8 h. There was no significant residual cytotoxicity or visual color change after soaking. SIGNIFICANCE: AgBr-NP@CTMAB showed promising potential treatment for denture cleaners.

Multifunctional Quaternary Phosphorus/Bromoargentate Hybrids: The Achievement of Greenish Blue Luminescence, Repeatable Photocurrent Responses and Durable Antimicrobial Activities with Enhanced Water Stability.

BACKGROUND: The realization of multifunction in one bulk material is fascinating for developing a new generation of devices. Quaternary phosphorus salts were seldom utilized as templates in haloargentate systems, and the hybridization of alkyl(triphenyl)phosphonium with halometallate will be a good strategy for the development of multifunctional material, especially for biological material. METHODS: Under the template of (triphenyl)phosphonium-based quaternary phosphorus salts with different spacer lengths (n=2, 3, 4), three bromoargentate hybrids were constructed via the solution method, ie, (1,2-DBTPP)(Ag2Br4) (1), {(1,3-DBTPP)2(Ag7Br11)]∙CH3CN∙H2O} n (2), and {[(1,4-DBTPP)(Ag5Br7)](CH3CN)2∙H2O} n (3) (1,2-DBTPP2+=ethane-1,2-diylbis (triphenyl)phosphonium, 1,3-DBTPP2+=propane-1,3-diylbis (triphenyl)phosphonium, 1,4-DBTPP2+=butane-1,4-diylbis (triphenyl)phosphonium)). RESULTS: The (Ag7Br11) n 4n- chain in 2 is a new type of 1-D bromoargentate chain constructed from cubane-like Ag4Br4 nodes, AgBr4 tetrahedrons and AgBr3 triangles. Interestingly, by elongating spacer n from 2 to 4, argentophilicity interactions are weakened, and the hydrogen bonds are strengthened. Consequently, their water stabilities and photocurrents are improved, in which the Ag-4d/Br-4p to π* anti-bonding orbital of the quaternary phosphorus transfer is facilitated. Furthermore, the greenish blue emissions can be detected. Finally, high inhabitation rates against Streptococcus mutans and Candida albicans can be observed in 2 and 3. CONCLUSION: In all experiments, by elongating the spacer lengths of quaternary phosphorus salts, multifunctions were integrated in the quaternary phosphorus/bromoargentate hybrids, including greenish blue luminescence, repeatable photocurrent responses and durable antimicrobial activities with enhanced water stability. This work could provide a theoretical guide for the design of new biologically multifunctional materials.

Core-Shell Structured Layered Lanthanide-Organic Complexes with Stilbazolium-type Dye Encapsulation for Multifunctional Performances.

Host-guest encapsulation of functional organic dye into a porous metal-organic framework can give rise to the development of new functional materials. In this work, by intercalating the stilbazolium-type dye (DEAST)I (4'-diethylamino-N-methyl stilbazolium) into four lanthanide layered metal-organic complexes (Ln-LMOCs), i. e. {[Ln(BTB)(H2 O)2 ]⋅3(DMF)⋅2(H2 O)}n (Ln=La (1), Nd (2), Sm (3), Er (4)), four responsive (DEAST)I@Ln-LMOC composites have been prepared, serving as multifunctional performance platform. The core-shell structures of (DEAST)I@Ln-LMOC composites have been fully characterized by IR, UV/Vis, PXRD, SEM, TEM, TGA and ESR. Significantly, after intercalation of dyes, the (DEAST)I@Ln-LMOC composites exhibit enhanced luminescent sensing properties in detecting Fe3+ with much higher water stabilities. The luminescent sensing behavior stems from the fluorescence resonance energy transfer (FRET) from the π-electron-rich BTB ligands to the Fe3+ , and their higher water stabilities are induced by electrostatic interactions and lower porosity. Specially, the characteristic emissions of Sm3+ will not be affected after the encapsulation guest dyes, which provide a theoretical guide for the modulation of luminescence devices. Finally, better ion conductivities and diminished photocurrents can be achieved after the embedding of the functional organic dye. In all, the formation of (DEAST)I@Ln-LMOC composites with core-shell structures can be utilized as a multifunctional platform with good stability.

The impact of metal cations on the photochemical properties of hybrid heterostructures with infinite alkaline-earth metal oxide clusters.

Donor-acceptor (D-A) hybrid heterostructures are an emerging class of hybrid complexes with potential applications in current optoelectronic technologies. To achieve high photoinduced charge-carrier generation and separation in a heterostructure, a common strategy is the fabrication of continuous or bicontinuous structures by the crystallization of semiconductive donor and acceptor tectons at the molecular level. So far, only a few such heterostructures have been fabricated, most of which involve unstable and narrow band gap metal halides. In this paper, we extended these unique hybrid heterostructures to continuous alkaline-earth metal oxide clusters. The combination of the naphthalene diimide (NDI) tecton bearing four carboxylates at two extremities with Ca2+ (or Sr2+) cations led to two isostructural D-A hybrid heterostructures with infinite 1-D carbon-doped alkaline-earth metal oxide clusters and X-aggregated NDI dimers as electron donors and acceptors, respectively. Due to the different metal cations in inorganic clusters, they exhibited diametrically opposite photochromic sensitivities and photocatalytic activities. To better rationalize them, a plausible photoinduced electron transfer process for the D-A hybrid heterostructures with photoactive acceptors has been developed.

Encapsulating Halometallates into 3-D Lanthanide-Viologen Frameworks: Controllable Emissions, Reversible Thermochromism, Photocurrent Responses, and Electrical Bistability Behaviors.

The encapsulation of guests into metal-organic frameworks (MOF) is an efficient strategy to generate novel multifunctional materials with enhanced properties. Herein, four halometallate@MOF composites with formulas of {(Pb2I4Br3)[(Pr(bpdo)4(H2O)2]·(H2O)}n (1), {[Pb3I10(H2O)2][Y2(bpdo)5(OH)2]·4(H2O)}n (2), {(Bi2I9)[(Pr(bpdo)3(H2O)]}n (3), {(Bi4I18)[(La(bpdo)4(H2O)2]2}n (4) (bpdo = 4,4'-bipyridine N,N'-dioxide) were prepared. In these composites, lanthanide-viologen MOF act as matrices, whose cavities were penetrated by halometallates. Consequently, the insertion of electron-rich halometallates into electron-deficient lanthanide-viologen matrices leads to the presence of strong room temperature charge transfer (CT) interactions. Importantly, these composites exhibit enhanced photo/thermal stabilities, controllable white emissions, reversible thermochromisms, and good photocurrent response performances. Specially, the memory devices based on these composites illustrate reversible electrical bistability behaviors, which can be assigned to ohmic and space-charge-limited conduction (SCLC) mechanisms. This kind of composite can be utilized as a multifunctional platform with enhanced stability.

Heterometallic Organic Frameworks Built from Trinuclear Indium and Cuprous Halide Clusters: Ligand-Oriented Assemblies and Iodine Adsorption Behavior.

Two novel heterometallic organic frameworks built from trinuclear indium and cuprous halide clusters, [(In3O)2(Cu2I2)3(ina)12(H2O)6](NO3)2·7DMA·10H2O (1) and [NH2(CH3)2][In3(OH)2(H2O)2(ina)8(Cu4I4)2]·5DMA·8H2O (2), where Hina = isonicotinic acid, have been successfully constructed with the orientation of the ina ligand. 1 shows a fascinating highly porous honeycomb-like 3D cationic framework with a trigonal-bipyramid-type cage based on a planar [In3O(CO2)6]+ trimer and a rhombohedral Cu2I2 cluster. Comparably, 2 displays a 3D negative network with irregular hexagonal channels constructed from a [In3(OH)2(CO2)8]- trimer and a cubane-like Cu4I4 cluster. Especially, 1 displays a reversible I2 adsorption/release performance with high adsorption capacity, whose mechanism has been disclosed by theoretical simulation. Also, the green/red emission of 2 stems from iodocuprate centers with quenched indium-centered emission.

A series of pure-blue-light emitting Cu(i) complexes with thermally activated delayed fluorescence: structural, photophysical, and computational studies.

Four mononuclear Cu(i)-halide complexes containing phosphines and pyridine ligands with strong electron donor substituents, [CuCl(PPh3)2(4-NMe2py)] (1), [CuI(PPh3)2(4-NH2py)] (2), [CuI(POP)(4-NH2py)] (3), and [CuI(POP)(4-NMe2py)]·0.5(Et2O) (4), (PPh3 = triphenylphosphine, 4-NMe2py = 4-(dimethylamino)pyridine, POP = bis[(2-diphenyl-phosphino)phenyl]ether, 4-NH2py = 4-aminopyridine, Et2O = diethyl ether) were synthesized and studied with regard to their structural, photophysical properties and theoretical calculations. The complexes exhibit pure blue thermally activated delayed fluorescence (λmax = 442 (1), 436 (2), 464 (3), and 448 nm (4)) in crystalline at room temperature. Emission lifetime analyses and density functional theory (DFT) calculations show that the blue-light emission at room temperature is the singlet (metal + halide)-to-ligand charge transfer state, (1(M + X)LCT), while that at 77 K is the state of 3(M + X)LCT transition character, owing to the small singlet-triplet energy gaps (ΔE = 660-1680 cm-1). X-ray diffraction structure analysis, photophysical studies and theoretical calculations suggest that the much larger torsion angle between the N-heterocyclic rings and N-Cu-X planes of complex 3 than that of 1, 2 and 4 might causes the bathochromic shift of luminescence, although these complexes containing similar heterocycle ligands.

ß-Arrestin-biased signaling mediates memory reconsolidation.

A long-standing hypothesis posits that a G protein-coupled signaling pathway mediates ß-adrenergic nervous system functions, including learning and memory. Here we report that memory retrieval (reactivation) induces the activation of ß1-adrenergic ß-arrestin signaling in the brain, which stimulates ERK signaling and protein synthesis, leading to postreactivation memory restabilization. ß-Arrestin2-deficient mice exhibit impaired memory reconsolidation in object recognition, Morris water maze, and cocaine-conditioned place preference paradigms. Postreactivation blockade of both brain ß-adrenergic Gs protein- and ß-arrestin-dependent pathways disrupts memory reconsolidation. Unexpectedly, selective blockade of the Gs/cAMP/PKA signaling but not the ß-arrestin/ERK signaling by the biased ß-adrenergic ligands does not inhibit reconsolidation. Moreover, the expression of ß-arrestin2 in the entorhinal cortex of ß-arrestin 2-deficient mice rescues ß1-adrenergic ERK signaling and reconsolidation in a G protein pathway-independent manner. We demonstrate that ß-arrestin-biased signaling regulates memory reconsolidation and reveal the potential for ß-arrestin-biased ligands in the treatment of memory-related disorders.

An unusual double T5(2) water tape trapped in silver(I) coordination polymer hosts: influence of the solvent on the assembly of Ag(I)-4,4'-bipyridine chains with trans-cyclohexanedicarboxylate and their luminescent properties.

In this paper, four silver(I) compounds, namely, {[Ag(4)(bipy)(4)(chda)]·2NO(3)·10H(2)O}(n) (1), {[Ag(2)(bipy)(2)(chda)]·14H(2)O}(n) (2), {[Ag(2)(bipy)(2)(chda)]·3EG·2H(2)O}(n) (3) and {[Ag(2)(bipy)(2)(chda)]·H(2)chda}(n) (4) (where bipy = 4,4'-bipyridine, H(2)chda = trans-cyclohexane-dicarboxylate and EG = ethylene glycol), have been synthesized and characterized by single-crystal X-ray diffraction analyses. In all of these compounds, the Ag(I) centers are linked by bipy ligands to form 1D Ag(I)-bipy chain structures. The chda(2-) anions of compound 1 adopt a µ(4)-coordination mode to connect the Ag(I)-bipy chains, forming a H-beam-like chain. In 2, the chda(2-) anions adopt a µ(2)-coordination mode to connect the Ag(I)-bipy chains resulting in two distinct 2D brick wall-like layers. These layers are further stacked in an ···ABAB··· fashion through interlayer π···π stacking interactions giving rise to a 3D framework consisting of quasi-rectangular channels, in which an unusual double T5(2) water tape is trapped. For 3 and 4, the chda(2-) anions show a similar µ(4)-coordination mode to that of 1 and connect the Ag(I)-bipy chains to form 2D grid layers with identical compositions and connective topologies. The experimental studies show that the final structures are greatly influenced by the molar ratio of the components and the solvents, which can be rationally interpreted by the existence of various supramolecular interactions between the host and guest molecules within these compounds through a systematic structural comparison. Additionally, the thermal stability and luminescent properties of these compounds were also studied.

Hybrid polymeric iodoplumbates constructed from morpholine and its derivatives: structures and properties.

Three hybrid polymeric iodoplumbates constructed from morpholine and its derivatives, {(Pb(4)I(15))[(Mph·H)(3)(Mph·1.5H)(2)]}(n)(1), {(edm-H(2))(Pb(3)I(8))]·2DMF}(n)(2), {(edm-H(2))[(dmp)(Pb(4)I(12))]˙2DMF}(n) (3) (Mph = morpholine, edm = ethylenedimorpholine, dmp(2+) = N,N'- dispiromorpholinopiperazonium) have been synthesized and structurally determined. In these compounds, morpholine and its derivatives weakly interact with or covalently bond to polymeric iodoplumbates. In 1, hydrogen bonds between (Pb(4)I(15))(7-) clusters and protonized Mph contribute to the formation of a 1-D hybrid chain. In 2, the 1-D [(Pb(3)I(8))](n)(2n-) chain is extended to be a 2-D layer via the edm(2+) ligand by means of Pb-O covalent bonds. Interestingly, the 2-D [(Pb(4)I(12))](n)(4n-) inorganic layer in 3 is concertedly templated by two kinds of organic cations. The above compounds exhibit a semiconductor nature, and third-order nonlinear optical (NLO) activities can be detected in 1 and 3.

Three silver iodides with zero and one-dimensional hybrid structures directed by conjugated organic templates: synthesis and theoretical study.

Under the direction of large conjugated organic cationic SDAs (structure-directing agents), three silver(I) iodides, (ipq)4(Ag2I6 x 2I2) (1), {[pql][Ag2I3]}n (2), [(npql)2(Ag4I6)]n (3) (ipq+ = N-(isopentyl)-quinolinium, pql+ = N-propyl-quinolinium, npql+ = N-(n-pentyl)-quinolinium) have been synthesized. 1 presents a zero-dimensional structure constituting of ipq+ cations, [Ag2I6]4- anions and molecular iodine. But 2 and 3 consist of one-dimensional coordination polymers that could be described as edge-sharing AgI4 tetrahedra. Electrostatic interactions between organic counter cations and inorganic moieties are present and contribute to the crystal packing. The structural differences between 1, 2 and 3 illustrate the influences of substituents of SDAs on the linkage modes of AgI4 tetrahedra. DFT calculations were carried out to reveal their electronic structures.

Environmental cues associated with morphine modulate release of glutamate and gamma-aminobutyric acid in ventral subiculum.

Objective To investigate whether environmental cues associated with different properties of morphine could regulate the extracellular levels of glutamate and gamma-aminobutyric acid (GABA) in the hippocampal ventral subiculum, which play a critical role in the reinstatement of drug-seeking behavior induced by environmental cues. Methods Conditioning place preference (CPP) and conditioning place aversion (CPA) models were used to establish environment associated with rewarding and aversive properties of morphine respectively. Microdialysis and high performance liquid chromatography were used to measure the extracelluar level of glutamate and GABA in the ventral subiculum under these environmental cues. Results Exposure to the environmental cues associated with rewarding properties of morphine resulted in a decrease (approximately 11%) of extracellular level of GABA in ventral subiculum, and exposure to the environmental cues associated with aversive properties of morphine resulted in an increase (approximately 230%) of extracellular level of glutamate in ventral subiculum. Conclusion Environmental cues associated with different properties of morphine modulate the release of distinct neurotransmitters in the hippocampal ventral subiculum possibly through different neural circuit.