The cholinergic anti-inflammatory pathway (CAP) is a neuro-immunomodulatory pathway,in which acetylcholine (ACh) released by the interaction of vagal nerves with α7 nicotinic acetylcholine receptor (α7nAChR),which prevents the synthesis and release of pro-inflammatory cytokines and ultimately regulates the local or systemic inflammatory response in a feedback manner. It has been shown that there are many possible effective treatments for sepsis, including vagus nerve stimulation by physical therapy, drugs such as acetylcholine receptor agonist and ultrasound therapy.
Acetylcholine ; Humans ; Inflammation ; Neuroimmunomodulation ; Sepsis ; Vagus Nerve Stimulation ; alpha7 Nicotinic Acetylcholine Receptor

It was reported that α7 nicotinic acetylcholine receptor (α7-nAChR) knockout (α7 KO) mice showed few functional phenotypes. The purpose of this study was to investigate the effect of α7 KO on the electrophysiological characteristics of hippocampus in mice. The effect of α7 KO on hippocampal CA3-CA1 synaptic transmission in mice was evaluated by standard extracellular field potential recordings. The electrophysiological phenotype of γ-aminobutyrate A receptors (GABA-Rs) of single hippocampal neuron was detected by perforated patch-clamp recordings. The results showed that, the slope of field excitatory postsynaptic potential (fEPSP) and carbachol-induced theta oscillation were significantly decreased in the hippocampal CA1 neurons of α7 KO mice, compared with those of wild type mice. Under the treatment of GABA-R agonist muscimol, the I-V curves of both the hippocampal CA1 and CA3 neurons of α7 KO mice shifted towards depolarizing direction obviously, compared with those of wild type mice. These results suggest that the hippocampal CA3-CA1 synaptic transmission in α7 KO mice was significantly impaired and GABA-R maturation was significantly delayed, indicating that the deletion of α7-nAChR gene could significantly change the electrophysiological function of the hippocampus. The results may provide a new understanding of the role of α7-nAChR in hippocampal function and associated diseases.
Animals ; Hippocampus ; cytology ; Mice ; Mice, Knockout ; Neurons ; physiology ; Phenotype ; Synaptic Transmission ; alpha7 Nicotinic Acetylcholine Receptor ; physiology

The autonomic nervous system consists of the sympathetic nervous system and the parasympathetic nervous system. These two systems control the heart and work in a reciprocal fashion to modulate myocardial energy metabolism, heart rate as well as blood pressure. Multiple cardiac pathological conditions are accompanied by autonomic imbalance, characterized by sympathetic overactivation and parasympathetic inhibition. Studies have shown that overactive sympathetic nervous system leads to increased cardiac inflammatory reaction. Orchestrated inflammatory response serves to clear dead cardiac tissue and activate reparative process, whereas excessive inflammation may result in pathological cardiac remodeling. Since the discovery of the α7 nicotinic acetylcholine receptor (α7nAChR)-mediated cholinergic anti-inflammatory pathway (CAP), the protective effects of the parasympathetic nervous system in cardiac inflammation have attracted more attention recently. In this review, we summarized the role and underlying mechanisms of the sympathetic and parasympathetic nervous systems in cardiac inflammation, in order to provide new insight into cardiac inflammatory response in cardiovascular diseases.
Autonomic Nervous System ; physiology ; Heart ; physiopathology ; Humans ; Inflammation ; physiopathology ; Parasympathetic Nervous System ; physiology ; alpha7 Nicotinic Acetylcholine Receptor ; physiology

OBJECTIVE: To construct a HIV-1 gp120 transgenic mouse model (gp120) with 7 nicotinic acetylcholine receptor (7nAChR) gene knockout. METHODS: The 7nAChR gene knockout mice (7R) were crossed with HIV-1gp120 transgenic mice (gp120) to generate F1 generation mice. We selected the F1 mice with the genotype of 7R/gp120 to mate to obtain the F2 mice. The genotypes of the F3 mice were identified by PCR, and the protein expressions in the double transgenic animal model was analyzed by immunohistochemistry. BV2 cells were treated with gp120 protein and 7nAChR inhibitor, and the expressions of IL-1β and TNF- were detected using ELISA. RESULTS: The results of PCR showed the bands of the expected size in F3 mice. Two F3 mice with successful double gene editing (7R/gp120) were obtained, and immunohistochemistry showed that the brain tissue of the mice did not express 7 nAChR but with high gp120 protein expression. In the cell experiment, treatment with gp120 promoted the secretion of IL-1β and TNF- in BV2 cells, while inhibition of 7nAChR significantly decreased the expression of IL-1β and TNF- ( < 0.001). CONCLUSIONS By mating gp120 Tg mice with 7R mice, we obtained gp120 transgenic mice with 7nAChR gene deletion, which serve as a new animal model for exploring the role of 7nAChR in gp120-induced neurotoxicity.
Animals ; Disease Models, Animal ; Glycoproteins ; Mice ; Mice, Knockout ; Mice, Transgenic ; Tumor Necrosis Factor-alpha ; alpha7 Nicotinic Acetylcholine Receptor ; metabolism

AIMTo establish the whole-cell recording techniques of the neuronal alpha4beta2, alpha4beta4, and alpha7-nicotinic acetylcholine receptors heterologously expressed in SH-EP1 cell line and discuss the electrophysiological characteristics of their open states.

METHODSThe cells were cultured with DEME medium(high glucose) and suitable for electrophysiological experiments three days after passage. The receptors were induced from resting states into open states by rapid application of nicotine (alpha4beta2, alpha4beta4) or choline (alpha7).

RESULTSThe SH-EP1 cells cultured by this method were in good conditions and expressed plenty of receptors. Alpha4beta2, alph4beta4 and alpha7 inward currents could be induced by rapid application of agonists but had different dynamic processes against time. All the three types of currents were dose and voltage-dependent and had inward rectification property.

CONCLUSIONThe open states of neuronal alpha4beta2, alpha4beta4, and alpha7-nicotinic acetylcholine receptors and their transitions have distinct characteristics and the inward currents of all this three types of receptors are dose and voltage-dependent and have inward rectification property.

Brain ; cytology ; metabolism ; Cell Line ; Epithelial Cells ; cytology ; Humans ; Membrane Potentials ; physiology ; Neurons ; cytology ; metabolism ; Patch-Clamp Techniques ; Receptors, Nicotinic ; physiology ; Transfection ; alpha7 Nicotinic Acetylcholine Receptor

Recent studies showed that Eph/Ephrin tyrosine kinase family plays an important role in the development and functional maintenance of the nervous system, but its function in the sympathetic nervous system is still obscure. In the present study, we examined the effect of Eph/Ephrin-B1 signaling on the whole-cell currents mediated by either alpha7 or alpha3-nicotinic acetylcholine receptors (nAChRs) in acutly dissociated ciliary ganglion (CG) neurons. Firstly, we detected the effect of Ephrin-B1 on nAChRs currents. The neurons were randomly divided into control group, Ephrin-B1Fc-treated group that was stimulated by recombinant Ephrin-B1Fc, IgG-treated group, and Ephrin-B1-treated group. Secondly, we studied the regulatory mechanism of Ephrin-B1Fc on nAChRs currents. The neurons were randomly divided into control group, Ephrin-B1Fc-treated group, PP2 (inhibitor of Src tyrosine kinase) or PD98095 (antagonist of mitogen-activated protein kinase)-treated group, Ephrin-B1Fc + PP2 or PD98095-treated group. The results showed that there was no significant difference between the currents in control group, IgG-treated group and Ephrin-B1-treated group, but Ephrin-B1Fc significantly suppressed both alpha3-nAChRs and alpha7-nAChRs-mediated currents (P=0.002, P=0.003). Pretreatment with PP2 or PD98095 could partially rescue the Ephrin-B1Fc-induced suppression of currents mediated by alpha3-nAChRs or alpha7-nAChRs respectively. These results suggest that the Eph/Ephrin-B1 signaling may inhibit alpha3-nAChRs and alpha7-nAChRs-mediated currents on CG neurons, involving Src tyrosine kinase and mitogen-activated protein kinase signaling in the regulation of sympathetic nervous system.
Ephrin-B1 ; metabolism ; Ganglia, Parasympathetic ; enzymology ; Mitogen-Activated Protein Kinases ; metabolism ; Neurons ; enzymology ; Receptors, Nicotinic ; metabolism ; Signal Transduction ; alpha7 Nicotinic Acetylcholine Receptor ; metabolism ; src-Family Kinases ; metabolism

BACKGROUNDInflammation is one of important mechanisms for myocardial ischemia reperfusion injury (IRI). Ischemia postconditioning (IPOC) can protect the heart against IRI by inhibiting inflammation, but its cardioprotection is weaker than that of ischemia preconditioning. Recently, the α7 subunit-containing nicotinic acetylcholine receptor (α7nAChR) agonist has shown anti-inflammatory effects in many diseases related to inflammation. This randomized controlled experiment was designed to evaluate whether combined postconditioning with IPOC and the α7nAChR agonist could produce an enhanced cardioprotection in a rat in vivo model of acute myocardial IRI.

METHODSFifty Sprague-Dawley rats were randomly divided into five equal groups: sham group, control group, IPOC group, α7nAChR agonist postconditioning group (APOC group) and combined postconditioning with IPOC and α7nAChR agonist group (combined group). Hemodynamic parameters were recorded during the periods of ischemia and reperfusion. Serum concentrations of troponin I (TnI), tumor necrosis factor α (TNF-α) and high-mobility group box 1 (HMGB-1) at 180 minutes after reperfusion were assayed in all groups. At the end of the experiment, the infarct size was assessed from excised hearts by Evans blue and triphenyl tetrazolium chloride staining.

RESULTSAs compared to the sham group, the infarct size in the other four groups was significantly increased, serum levels of TnI, TNF-α and HMGB1 in the control group and TNF-α, HMGB1 in the IPOC group were significantly increased. The infarct size and serum concentrations of TNF-α, HMGB1 and TnI in the IPOC, APOC and combined groups were significantly lower than those in the control group. As compared to the IPOC group, the infarct size in the combined group was significantly decreased, serum concentrations of TnI, TNF-α and HMGB1 in the APOC and combined groups were significantly reduced. Although the infarct size was significantly smaller in the combined group than in the APOC group, serum levels of TNF-α and HMGB1 were significantly higher in the combined group than in the APOC group.

CONCLUSIONSIn a rat in vivo model of acute myocardial IRI, combined postconditioning with IPOC and the α7nAChR agonist can produce enhanced protection against myocardial IRI by increasing the anti-inflammatory effect.

Animals ; Heart ; drug effects ; Ischemic Preconditioning, Myocardial ; methods ; Male ; Myocardial Reperfusion Injury ; prevention & control ; Myocardium ; pathology ; Nicotinic Agonists ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Receptors, Nicotinic ; metabolism ; Tumor Necrosis Factor-alpha ; blood ; alpha7 Nicotinic Acetylcholine Receptor

The effects of presynaptic nicotinic acetylcholine receptors (nAChRs) on excitatory synaptic transmission in CA1 pyramidal neurons of the rat hippocampus were examined by blind whole-cell patch clamp recording from hippocampal slice preparations. Local application of the nAChRs agonist dimethylphenyl-piperazinium iodide (DMPP) did not induce a postsynaptic current response in CA1 pyramidal cells. However, DMPP enhanced the frequency and amplitude of spontaneous excitatory postsynaptic current (sEPSC) in these cells in a dose-dependent manner. This enhancement was blocked by the selective nicotinic alpha-7 receptor antagonist alpha-bungarotoxin, but not by the antagonist mecamylamine, hexamethonium or dihydro-beta-erythroidine. The frequency of miniature excitatory postsynaptic current (mEPSC) in CA1 pyramidal neurons was also increased by application of DMPP, indicating a presynaptic site of action of the agonist. Taken together, these results suggest that activation of presynaptic nAChRs in CA1 pyramidal neurons, which contain alpha-7 subunits, potentiates presynaptic glutamate release and consequently modulate excitatory synaptic transmission in the hippocampus.
Animals ; Bungarotoxins ; physiology ; Dimethylphenylpiperazinium Iodide ; pharmacology ; Glutamic Acid ; pharmacology ; Hippocampus ; physiology ; Male ; Neurons ; physiology ; Nicotinic Agonists ; pharmacology ; Pacemaker, Artificial ; Patch-Clamp Techniques ; Rats ; Rats, Wistar ; Receptors, Nicotinic ; physiology ; Receptors, Presynaptic ; physiology ; Synapses ; physiology ; Synaptic Transmission ; alpha7 Nicotinic Acetylcholine Receptor

The cholinergic anti-inflammatory pathway (CAP) is a neurophysiological mechanism that regulates the immune system. The CAP inhibits inflammation by suppressing cytokine synthesis via release of acetylcholine in organs of the reticuloendothelial system, including the lungs, spleen, liver, kidneys and gastrointestinal tract. Acetylcholine can interact with alpha7 nicotinic acetylcholine receptors (alpha7 nAchR) expressed by macrophages and other cytokine producing cells, down-regulate pro-inflammatory cytokine synthesis and prevent tissue damage. Herein is a review of the neurophysiological mechanism in which the CAP regulates inflammatory response, as well as its potential interventional strategy for inflammatory diseases.
Acetylcholine ; pharmacology ; Animals ; Humans ; Inflammation ; immunology ; prevention & control ; Myocardial Infarction ; immunology ; Pancreatitis ; immunology ; Receptors, Muscarinic ; physiology ; Receptors, Nicotinic ; physiology ; Reperfusion Injury ; immunology ; Sepsis ; immunology ; Shock, Hemorrhagic ; immunology ; Spleen ; immunology ; innervation ; Vagus Nerve ; physiology ; alpha7 Nicotinic Acetylcholine Receptor

The present study was to explore the temporal and spatial distributions and variations of α7 nicotinic acetylcholine receptor (α7nAChR) and neuronal nitric oxide synthetase (nNOS) in cerebral cortex and hippocampus of Aβ-induced cognitive dysfunction rats. Sixty Sprague-Dawley (SD) rats were randomly divided into six groups. Three experimental groups were intracerebroventricularly (i.c.v.) injected with condensed-amyloid beta peptides 1-42 (Aβ, 2.5 µg/µL, 4 µL) and were observed on day 7 (7 d Aβ group), day 14 (14 d Aβ group) and day 21 (21 d Aβ group), respectively. Three control groups were i.c.v. injected with equivalent volume of normal saline and observed at the same time points as the experimental groups. The learning and memory abilities of rats were tested with Y-maze; the locations and protein expression levels of α7nAChR and nNOS in cerebral cortex and hippocampal CA1, CA3, DG regions were measured by immunohistochemistry and Western blot, respectively. The result showed that, compared with the control groups, the three experimental groups exhibited decreased learning and memory behavioral abilities, and down-regulated expressions of nNOS and α7nAChR in prefrontal cortex and hippocampal regions, especially in superficial layer of prefrontal cortex and hippocampal CA3 region. Comparisons among the three experimental groups showed that the inhibitory effects of Aβ on the abilities of learning and memory and the expressions of α7nAChR and nNOS in prefrontal cortex and hippocampus were time dependent. The results suggest that the coincident declines of α7nAChR and nNOS in prefrontal cortex and hippocampus may be the foundations of the cognitive dysfunction.
Amyloid beta-Peptides ; Animals ; Cerebral Cortex ; Cognitive Dysfunction ; Hippocampus ; Learning ; Memory ; Nitric Oxide Synthase Type I ; Rats ; Rats, Sprague-Dawley ; alpha7 Nicotinic Acetylcholine Receptor