Autoradiographic Analysis of GABAA Receptors in μ-Opioid Receptor Knockout Mice

Anatomical evidence indicates that γ-aminobutyric acid (GABA)-ergic and opioidergic systems are closely linked and act on the same neurons. However, the regulatory mechanisms between GABAergic and opioidergic system have not been well characterized. In the present study, we investigated whether there are changes in GABA_A receptors in mice lacking μ-opioid receptor gene. The GABA_A receptor binding was carried out by autoradiography using [³H]-muscimol (GABA_A), [³H]-flunitrazepam (FNZ, native type 1 benzodiazepine) and [³⁵S]-t-butylbicyclophosphorothionate (TBPS, binding to GABA_A-gated chloride channels) in brain slices of wild type and μ-opioid receptor knockout mice. The binding of [³H]-FNZ in μ-opioid receptor knockout mice was significantly higher than that of the wild type controls in most of the cortex and hippocampal CA1 and CA2 formations. μ-Opioid receptor knockout mice show significantly lower binding of [³⁵S]-TBPS than that of the wild type mice in few of the cortical areas including ectorhinal cortex layers I, III, and V, but not in the hippocampus. There was no significant difference in binding of [³H]-muscimol between μ-opioid receptor knockout and wild type mice in the cortex and hippocampus. These data indicate that there are specific regional changes in GABA_A receptor binding sites in μ-opioid receptor knockout mice. These data also suggest that there are compensatory up-regulation of benzodiazepine binding site of GABA_A receptors in the cortex and hippocampus and down-regulation of GABA-gated chloride channel binding site of GABA_A receptors in the cortex of the μ-opioid receptor knockout mice.     

Tolerance to Diazepam-Induced Motor Impairment: A Study with GABAA Receptor α6 Subunit Knockout Mice

Development of tolerance to motor-impairing effects of repeated administration of moderate diazepam doses (5.0–7.5 mg/kg; three times daily PO 3 weeks) was compared between mice deficient in the cerebellar granule cell–restricted GABA_A receptor 6 subunit and their wild-type controls. The 6–/– mice were more impaired by the initial challenge doses of diazepam (5 or 10 mg/kg) than their controls, but acquired partial tolerance by the second tests with the same doses 4–7 days later. Chronic treatment produced complete tolerance in both mouse lines. Ligand autoradiography revealed a significant reduction in baseline benzodiazepine and chloride channel site-bindings in various regions of the 6–/– brains, but the chronic diazepam treatment did not consistently alter baseline or benzodiazepine site agonist and inverse agonist-modulated binding in the 6–/– and wildtype mice. The results indicate that tolerance to motor-impairing actions of diazepam is independent of the diazepam-insensitive 6 subunit-containing receptors, which rules out the possibility that tolerance emerges as an increase in structurally benzodiazepine-insensitive receptor population.     

Altered GABAA Receptor Expression and Seizure Threshold Following Acute Ethanol Challenge in Mice Lacking the RIIβ Subunit of PKA

Ethanol causes pathological changes in GABA_A receptor trafficking and function. These changes are mediated in part by ethanol activation of protein kinase A (PKA). The current study investigated the expression of the GABA_A α1 and α4 subunits and the kinase anchoring protein AKAP150, as well as bicuculline-induced seizure threshold, at baseline and following acute injection of ethanol (3.5 g/kg IP) in a mouse line lacking the regulatory RIIβ subunit of PKA. Whole cerebral cortices were harvested at baseline, 1 h, or 46 h following injection of ethanol or saline and subjected to fractionation and western blot analysis. Knockout (RIIβ?/?) mice had similar baseline levels of PKA RIIα and GABA_A α1 and α4 subunits compared to wild type (RIIβ+/+) littermates, but had deficits in AKAP150. GABA_A α1 subunit levels were decreased in the P2 fraction of RIIβ?/?, but not RIIβ+/+, mice following 1 h ethanol, an effect that was driven by decreased α1 expression in the synaptic fraction. GABA_A α4 subunits in the P2 fraction were not affected by 1 h ethanol; however, synaptic α4 subunit expression was increased in RIIβ+/+, but not RIIβ?/? mice, while extrasynaptic α4 and δ subunit expression were decreased in RIIβ?/?, but not RIIβ+/+ mice. Finally, RIIβ knockout was protective against bicuculline-induced seizure susceptibility. Overall, the results suggest that PKA has differential roles in regulating GABA_A receptor subunits. PKA may protect against ethanol-induced deficits in synaptic α1 and extrasynaptic α4 receptors, but may facilitate the increase of synaptic α4 receptors.     

Barbiturates Require the N Terminus and First Transmembrane Domain of the δ Subunit for Enhancement of α1β3δ GABAA Receptor Currents

GABA_A receptors are composed predominantly of αβγ receptors, which mediate primarily synaptic inhibition, and αβδ receptors, which mediate primarily extrasynaptic inhibition. At saturating GABA concentrations, the barbiturate pentobarbital substantially increased the amplitude and desensitization of the α1β3δ receptor but not the α1β3γ2L receptor currents. To explore the structural domains of the δ subunit that are involved in pentobarbital potentiation and increased desensitization of α1β3δ currents, chimeric cDNAs were constructed by progressive replacement of γ2L subunit sequence with a δ subunit sequence or a δ subunit sequence with a γ2L subunit sequence, and HEK293T cells were co-transfected with α1 and β3 subunits or α1 and β3 subunits and a γ2L, δ, or chimeric subunit. Currents evoked by a saturating concentration of GABA or by co-application of GABA and pentobarbital were recorded using the patch clamp technique. By comparing the extent of enhancement and changes in kinetic properties produced by pentobarbital among chimeric and wild type receptors, we concluded that although potentiation of α1β3δ currents by pentobarbital required the δ subunit sequence from the N terminus to proline 241 in the first transmembrane domain (M1), increasing desensitization of α1β3δ currents required a δ subunit sequence from the N terminus to isoleucine 235 in M1. These findings suggest that the δ subunit N terminus and N-terminal portion of the M1 domain are, at least in part, involved in transduction of the allosteric effect of pentobarbital to enhance α1β3δ currents and that this effect involves a distinct but overlapping structural domain from that involved in altering desensitization.     

Altered Astrocytic Swelling in the Cortex of α-Syntrophin-Negative GFAP/EGFP Mice

Brain edema accompanying ischemic or traumatic brain injuries, originates from a disruption of ionic/neurotransmitter homeostasis that leads to accumulation of K⁺ and glutamate in the extracellular space. Their increased uptake, predominantly provided by astrocytes, is associated with water influx via aquaporin-4 (AQP4). As the removal of perivascular AQP4 via the deletion of α-syntrophin was shown to delay edema formation and K⁺ clearance, we aimed to elucidate the impact of α-syntrophin knockout on volume changes in individual astrocytes in situ evoked by pathological stimuli using three dimensional confocal morphometry and changes in the extracellular space volume fraction (α) in situ and in vivo in the mouse cortex employing the real-time iontophoretic method. RT-qPCR profiling was used to reveal possible differences in the expression of ion channels/transporters that participate in maintaining ionic/neurotransmitter homeostasis. To visualize individual astrocytes in mice lacking α-syntrophin we crossbred GFAP/EGFP mice, in which the astrocytes are labeled by the enhanced green fluorescent protein under the human glial fibrillary acidic protein promoter, with α-syntrophin knockout mice. Three-dimensional confocal morphometry revealed that α-syntrophin deletion results in significantly smaller astrocyte swelling when induced by severe hypoosmotic stress, oxygen glucose deprivation (OGD) or 50 mM K⁺. As for the mild stimuli, such as mild hypoosmotic or hyperosmotic stress or 10 mM K⁺, α-syntrophin deletion had no effect on astrocyte swelling. Similarly, evaluation of relative α changes showed a significantly smaller decrease in α-syntrophin knockout mice only during severe pathological conditions, but not during mild stimuli. In summary, the deletion of α-syntrophin markedly alters astrocyte swelling during severe hypoosmotic stress, OGD or high K⁺.     

Comparative Analysis of MPTP Neurotoxicity in Mice with a Constitutive Knockout of the α-Synuclein Gene

Molecular Biology - Aggregated forms of α-synuclein are core components of pathohistological inclusions known as Lewy bodies in substantia nigra (SN) neurons of patients with Parkinson’s...     

Changes in Expression of GABAA α4 Subunit mRNA in the Brain under Anesthesia Induced by Volatile and Intravenous Anesthetics

We investigated changes in levels of GABA_A receptor α4 subunit mRNA in the mouse brain after administration of volatile or i.v. anesthetic, by performing quantitative RT-PCR. We also performed immunohistochemical assays for c-fos-like protein. During deep anesthesia (which was estimated by loss of righting reflex) after administration of propofol, levels of GABA_A receptor α4 subunit mRNA in the hippocampus, striatum and diencephalons were significantly greater than those observed after administration of pentobarbital, midazolam or GOI (5.0% isoflurane and 70% nitrous oxide in oxygen). Under incomplete anesthesia, levels of GABA_A receptor α4 subunit mRNA were significantly increased by midazolam in all brain regions, and were significantly increased by pentobarbital in the posterior cortex and striatum. Expression of GABA_A receptor α4 subunit mRNA closely correlated with expression of c-fos-like protein. These results indicate that the GABA_A receptor α4 subunit plays an important role in regulating the anesthetic stage of i.v. anesthetics.     

Characterization of the Testis-specific Proteasome Subunit α4s in Mammals

The 26 S proteasome is responsible for regulated proteolysis in eukaryotic cells. It is composed of one 20 S core particle (CP) flanked by one or two 19 S regulatory particles. The CP is composed of seven different α-type subunits (α1-α7) and seven different β-type subunits, three of which are catalytic. Vertebrates encode four additional catalytic β subunits that are expressed predominantly in immune tissues and produce distinct subtypes of CPs particularly well suited for the acquired immune system. In contrast, the diversity of α subunits remains poorly understood. Recently, another α subunit, referred to as α4s, was reported. However, little is known about α4s. Here we provide a detailed characterization of α4s and the α4s-containing CP. α4s is exclusively expressed in germ cells that enter the meiotic prophase and is incorporated into the CP in place of α4. A comparison of structural models revealed that the differences in the primary sequences between α4 and α4s are located on the outer surface of the CP, suggesting that α4s interacts with specific molecules via these unique regions. α4s-containing CPs account for the majority of the CPs in mouse sperm. The catalytic β subunits in the α4s-containing CP are β1, β2, and β5, and immunosubunits are not included in the α4s-containing CP. α4s-containing CPs have a set of peptidase activities almost identical to those of α4-containing CPs. Our results provide a basis for understanding the role of α4s and male germ cell-specific proteasomes in mammals.     

Variants of the α6 β1 Laminin Receptor in Early Murine Development: Distribution,Molecular Cloning and Chromosomal Localization of the Mouse Integrin α6 Subunit

Laminin (A:B1:B2) is a major component of the first basement membrane to appear in the developing mouse embryo. Its effects on morphogenesis and differentiation are mediated by interaction with cell surface receptors that are members of the integrin family. We have studied the expression of the α₆ subunit of murine α₆β₁ and its ligand, laminin, in preimplantation mouse embryos, embryo outgrowths and in embryonic stem (ES) cells and embryonal carcinoma (EC) cells. The α₆ subunit is present in the oocyte and throughout preimplantation development. Laminin A chain appears later than α₆ and has a more restricted distribution until the late blastocyst stage. α₆β₁ is strongly expressed in ES and EC cells; the levels of mRNA expression are not altered by differentiation. Molecular cloning of cDNA for the murine integrin α₆ subunit from a mammary gland γt11 library showed, as in man, an open reading frame encoding two variants of α₆, α₆ and α_6B. The identity of the α₆ amino acid sequence to that in man and chicken is 93% and 73%, respectively. The gene for murine α₆ was mapped to chromosome 2. While undifferentiated ES and EC cells express only α_6B, α_6A is co-expressed in ES cells after differentiation is induced by retinoic acid. α_6B is also the only variant expressed in blastocyst stage embryos, but when blastocysts have grown out in culture both α_6A and α_6B are expressed reflecting the results in the cell lines. We suggest that the deposition of laminin in the embryo is a receptor-mediated process and that the shift in the expression of the variants, as the inner cell mass forms its first differentiated progeny, reflects a change in functional properties.     

Complementation of α-thalassaemia in α-globin Knockout Mice with a 191 kb Transgene Containing the Human α-Globin Locus

alpha-thalassaemia is an inherited blood disorder caused by a decrease in the synthesis of alpha-globin due to mutations in one or both of the alpha-globin genes located on human chromosome 16. A 191 kb transgene derived from a sequenced bacterial artificial chromosome (BAC) clone carrying the human alpha-globin gene cluster, together with about 100 kb of sequence upstream of DNase1 hypersensitive site HS-40 and 30 kb downstream of the alpha1-globin gene, was introduced into fertilised mouse oocytes by pronuclear microinjection. Three transgenic founder mice were obtained. Analysis of one transmitting line by fluorescent in situ hybridisation and quantitative PCR demonstrated a single copy integration of the human alpha-globin transgene on chromosome 1. Analysis of haemoglobins from the peripheral blood by cellulose acetate electrophoresis and high performance liquid chromatography (HPLC) demonstrated synthesis of human alpha-globin to about 36% of the level of each mouse alpha-globin locus. Breeding of transgenic mice with mice heterozygous for a knockout (KO) deletion of both murine alpha-globin genes showed that the human alpha-globin locus restored haemoglobin levels and red cell distribution width to normal in double heterozygous mice and significantly normalised other haematological parameters. Interestingly the human transgene also induced a significant increase in red cell production and haematocrit above wild type values. This is the first report demonstrating complementation of a murine alpha-globin KO mutation by human alpha-globin gene expression from an intact human alpha-globin locus. The transgenic mouse model described in this report should be very useful for the study of human alpha-globin gene regulation and for the development of strategies to down regulate alpha-globin production as a means of ameliorating the severity of beta-thalassaemia.     

Determinants in the β and δ Subunit Cytoplasmic Loop Regulate Golgi Trafficking and Surface Expression of the Muscle Acetylcholine Receptor

The molecular determinants that govern nicotinic acetylcholine receptor (AChR) assembly and trafficking are poorly defined, and those identified operate largely during initial receptor biogenesis in the endoplasmic reticulum. To identify determinants that regulate later trafficking steps, we performed an unbiased screen using chimeric proteins consisting of CD4 fused to the muscle AChR subunit cytoplasmic loops. In C2 mouse muscle cells, we found that CD4-β and δ subunit loops were expressed at very low levels on the cell surface, whereas the other subunit loops were robustly expressed on the plasma membrane. The low surface expression of CD4-β and δ loops was due to their pronounced retention in the Golgi apparatus and also to their rapid internalization from the plasma membrane. Both retention and recovery were mediated by the proximal 25–28 amino acids in each loop and were dependent on an ordered sequence of charged and hydrophobic residues. Indeed, βK353L and δK351L mutations increased surface trafficking of the CD4-subunit loops by >6-fold and also decreased their internalization from the plasma membrane. Similarly, combined βK353L and δK351L mutations increased the surface levels of assembled AChR expressed in HEK cells to 138% of wild-type levels. This was due to increased trafficking to the plasma membrane and not decreased AChR turnover. These findings identify novel Golgi retention signals in the β and δ subunit loops that regulate surface trafficking of assembled AChR and may help prevent surface expression of unassembled subunits. Together, these results define molecular determinants that govern a Golgi-based regulatory step in nicotinic AChR trafficking.     

Localization and synthesis of α-fetoprotein in the chicken

Summary The localization and sites of synthesis of -fetoprotein in chick embryos throughout development have been investigated using the combined techniques of immunofluorescence microscopy and tissue culture in the presence of radiolabelled amino acids, followed by immunoautoradiographic analysis.Alpha-fetoprotein is present in a range of embryonic tissues and especially concentrated in the yolk sac, liver and connective tissue. Analysis of culture fluids revealed that the yolk sac is the major site of -fetoprotein synthesis with smaller, but significant quantities being produced by the liver.These results are discussed in relation to mammalian -fetoprotein, and the merits of the chick embryo for studies on the biological function of AFP are considered.Supported by an award from the Science Research Council, to whom grateful acknowledgement is made     

Altered Social Behaviours in Neurexin 1α Knockout Mice Resemble Core Symptoms in Neurodevelopmental Disorders

Background

Copy number variants have emerged as an important genomic cause of common, complex neurodevelopmental disorders. These usually change copy number of multiple genes, but deletions at 2p16.3, which have been associated with autism, schizophrenia and mental retardation, affect only the neurexin 1 gene, usually the alpha isoform. Previous analyses of neurexin 1α (Nrxn1α) knockout (KO) mouse as a model of these disorders have revealed impairments in synaptic transmission but failed to reveal defects in social behaviour, one of the core symptoms of autism.

Methods

We performed a detailed investigation of the behavioural effects of Nrxn1α deletion in mice bred onto a pure genetic background (C57BL/6J) to gain a better understanding of its role in neurodevelopmental disorders. Wildtype, heterozygote and homozygote Nrxn1α KO male and female mice were tested in a battery of behavioural tests (n = 9–16 per genotype, per sex).

Results

In homozygous Nrxn1α KO mice, we observed altered social approach, reduced social investigation, and reduced locomotor activity in novel environments. In addition, male Nrxn1α KO mice demonstrated an increase in aggressive behaviours.

Conclusions

These are the first experimental data that associate a deletion of Nrxn1α with alterations of social behaviour in mice. Since this represents one of the core symptom domains affected in autism spectrum disorders and schizophrenia in humans, our findings suggest that deletions within NRXN1 found in patients may be responsible for the impairments seen in social behaviours, and that the Nrxn1α KO mice are a useful model of human neurodevelopmental disorder.     

Subunit Interacting Surfaces of Human Hemoglobin in Solution: Localization of the α–β Subunit Interacting Surfaces on the α-Chain by a Comprehensive Synthetic Strategy

By using synthetic overlapping peptides encompassing the entire -chain of adult human hemoglobin (HbA), we have mapped on the -chain the regions responsible for its binding to the -chain in solution. These binding surfaces were, in general, in good agreement with those expected from the crystal structure (peptides 81–95, 101–115, 111–125, and 131–141). However, we observed some significant differences in the levels of binding found here in solution and those expected from the crystal structure. Peptide 31–45, which in the crystal had the highest number of contact residues of all the -chain peptides, did not bind the -chain in solution. Similarly, peptide 91–105, with seven contact residues in the crystal, showed low binding with the -chain in solution. On the other hand, peptides 41–55 and 121–135 possessed much higher binding activity in solution than would be expected from their contribution to subunit association in the crystal. In fact, peptide 121–135 had the highest binding activity of the -chain peptides. These studies and our previous findings, which localized on the -chain the regions that bind to the -chain in solution, have shown that the regions of subunit association in solution are close to, but not identical with, those in the crystal. The approach should be quite useful for mapping subunit association in oligomeric proteins and could even be applied to proteins that are isolated only in traces or whose three-dimensional structure is not yet known.     

GABAA Receptor α1 Subunit Mutation A322D Associated with Autosomal Dominant Juvenile Myoclonic Epilepsy Reduces the Expression and Alters the Composition of Wild Type GABAA Receptors

A GABA_A receptor (GABA_AR) α1 subunit mutation, A322D (AD), causes an autosomal dominant form of juvenile myoclonic epilepsy (ADJME). Previous studies demonstrated that the mutation caused α1(AD) subunit misfolding and rapid degradation, reducing its total and surface expression substantially. Here, we determined the effects of the residual α1(AD) subunit expression on wild type GABA_AR expression to determine whether the AD mutation conferred a dominant negative effect. We found that although the α1(AD) subunit did not substitute for wild type α1 subunits on the cell surface, it reduced the surface expression of α1β2γ2 and α3β2γ2 receptors by associating with the wild type subunits within the endoplasmic reticulum and preventing them from trafficking to the cell surface. The α1(AD) subunit reduced surface expression of α3β2γ2 receptors by a greater amount than α1β2γ2 receptors, thus altering cell surface GABA_AR composition. When transfected into cultured cortical neurons, the α1(AD) subunit altered the time course of miniature inhibitory postsynaptic current kinetics and reduced miniature inhibitory postsynaptic current amplitudes. These findings demonstrated that, in addition to causing a heterozygous loss of function of α1(AD) subunits, this epilepsy mutation also elicited a modest dominant negative effect that likely shapes the epilepsy phenotype.     

Lynx1 Shifts α4β2 Nicotinic Receptor Subunit Stoichiometry by Affecting Assembly in the Endoplasmic Reticulum

Glycosylphosphatidylinositol-anchored neurotoxin-like receptor binding proteins, such as lynx modulators, are topologically positioned to exert pharmacological effects by binding to the extracellular portion of nAChRs. These actions are generally thought to proceed when both lynx and the nAChRs are on the plasma membrane. Here, we demonstrate that lynx1 also exerts effects on α4β2 nAChRs within the endoplasmic reticulum. Lynx1 affects assembly of nascent α4 and β2 subunits and alters the stoichiometry of the receptor population that reaches the plasma membrane. Additionally, these data suggest that lynx1 shifts nAChR stoichiometry to low sensitivity (α4)₃(β2)₂ pentamers primarily through this interaction in the endoplasmic reticulum, rather than solely via direct modulation of activity on the plasma membrane. To our knowledge, these data represent the first test of the hypothesis that a lynx family member, or indeed any glycosylphosphatidylinositol-anchored protein, could act within the cell to alter assembly of a multisubunit protein.     

Hippocampal Damage Disrupts Eyeblink Conditioning in Mice Lacking Glutamate Receptor Subunit δ2

Cerebellar long-term depression (LTD) at the parallel fiber-Purkinje cell synapses has been proposed to be a neural substrate for classical eyeblink conditioning. Mutant mice lacking the glutamate receptor subunit 2 (GluR2), in which the cerebellar LTD is disrupted, exhibited a severe impairment in the delay eyeblink conditioning with a temporal overlap of CS and US. However, they learned normally trace and delay conditioning without CS-US overlap, suggesting a learning mechanism which does not require the cerebellar LTD.In the present study, we tested possible involvement of the hippocampus in this cerebellar LTD-independent learning. We examined effects of scopolamine and hippocampal lesion on the delay conditioning without CS-US overlap. TheGluR2 mutant mice that received scopolamine or aspiration of the dorsalhippocampus together with its overlying cortex exhibited a severe impairment in learning, while the control mutant mice that received saline or aspiration of the overlying cortex learned normally. In contrast, wild-type mice that received either treatment learned as normally as the control wild-type mice. These results suggest that the hippocampus is essential in the cerebellar LTD-independent learning in the GluR2 mutant mice, indicating a newrole of hippocampus in the paradigm with a short trace interval.     

Alternative-Splicing in the Exon-10 Region of GABAA Receptor β2 Subunit Gene: Relationships between Novel Isoforms and Psychotic Disorders

Background

Non-coding single nucleotide polymorphisms (SNPs) in GABRB2, the gene for β₂-subunit of gamma-aminobutyric acid type A (GABA_A) receptor, have been associated with schizophrenia (SCZ) and quantitatively correlated to mRNA expression and alternative splicing.

Methods and Findings

Expression of the Exon 10 region of GABRB2 from minigene constructs revealed this region to be an “alternative splicing hotspot” that readily gave rise to differently spliced isoforms depending on intron sequences. This led to a search in human brain cDNA libraries, and the discovery of two novel isoforms, β_2S1 and β_2S2, bearing variations in the neighborhood of Exon-10. Quantitative real-time PCR analysis of postmortem brain samples showed increased β_2S1 expression and decreased β_2S2 expression in both SCZ and bipolar disorder (BPD) compared to controls. Disease-control differences were significantly correlated with SNP rs187269 in BPD males for both β_2S1 and β_2S2 expressions, and significantly correlated with SNPs rs2546620 and rs187269 in SCZ males for β_2S2 expression. Moreover, site-directed mutagenesis indicated that Thr³⁶⁵, a potential phosphorylation site in Exon-10, played a key role in determining the time profile of the ATP-dependent electrophysiological current run-down.

Conclusion

This study therefore provided experimental evidence for the importance of non-coding sequences in the Exon-10 region in GABRB2 with respect to β₂-subunit splicing diversity and the etiologies of SCZ and BPD.     

Stimulation of the α7 Nicotinic Acetylcholine Receptor Protects against Neuroinflammation after Tibia Fracture and Endotoxemia in Mice

Surgery and critical illness often associate with cognitive decline. Surgical trauma or infection can lead independently to learning and memory impairments via similar, but not identical, cellular signaling of the innate immune system that promotes neuroinflammation. In this study we explored the putative synergism between aseptic orthopedic surgery and infection, the latter reproduced by postoperative lipopolysaccharide (LPS) administration. We observed that surgery and LPS augmented systemic inflammation up to postoperative d 3 and this was associated with further neuroinflammation (CD11b and CD68 immunoreactivity) in the hippocampus in mice compared with those receiving surgery or LPS alone. Administration of a selective α7 subtype nicotinic acetylcholine receptor (α7 nAChR) agonist 2 h after LPS significantly improved neuroinflammation and hippocampal-dependent memory dysfunction. Modulation of nuclear factor-kappa B (NF-κB) activation in monocytes and regulation of the oxidative stress response through nicotinamide adenine dinucleotide phosphate (NADPH) signaling appear to be key targets in modulating this response. Overall, these results suggest that it may be conceivable to limit and possibly prevent postoperative complications, including cognitive decline and/or infections, through stimulation of the cholinergic antiinflammatory pathway.