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acetylcholine


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  • Acetylcholine prevents intercellular adhesion molecule 1 (CD54)-induced focal adhesion complex assembly in endothelial cells via a nitric oxide-cGMP-dependent pathway. 11037885

    OBJECTIVE: Nitric oxide (NO) is induced by exposure of endothelial cells (EC) to acetylcholine, where it acts in a paracrine manner to relax smooth muscle and as a defensive molecule to inhibit the adhesion of leukocytes to EC. The mechanism(s) of the antiadhesive properties of constitutive NO are poorly understood. In these studies, we found that NO induced by acetylcholine exerts autocrine effects, which interfere with normal adhesion mechanisms. METHODS: The function of the adhesion molecule intercellular adhesion molecule 1 (CD54) of EC was measured using latex beads coated with antibody to CD54 as a model for CD54 ligation by the leukocyte beta2 integrin. Recruitment of filamentous actin (F-actin) and of the signaling molecule vasodilator-stimulated phosphoprotein (VASP) was measured by immunofluorescence microscopy. RESULTS: Exposure of EC to anti-CD54 beads induced the subplasmalemmal assembly of F-actin and VASP. Acetylcholine blocked the anti-CD54 bead-induced translocation of F-actin and VASP; this effect was reversed by inhibition of NO production. The NO action did not interfere with binding, but completely inhibited the assembly of the focal activation complex, which we believe is necessary for firm heterotypic adhesion between leukocyte and EC. Further studies indicated that the NO effect was due to its capacity to raise cGMP. Platelet endothelial cell adhesion molecule 1 (CD31, also implicated in leukocyte adhesion) did not mimic CD54 responses. CONCLUSION: These results indicate that the ligation of endothelial cell CD54 induces the assembly of subplasmalemmal F-actin and the recruitment of VASP. NO derived from constitutive nitric oxide synthase acts to disrupt these CD54-elicited endothelial cell responses. This action may protect vascular endothelium from leukocyte-mediated injury.
    문서 타입:
    Reference
    카탈로그 번호:
    AP192
  • Acetylcholine synthesis by choline acetyltransferase of a peripheral type as demonstrated in adult rat dorsal root ganglion. 17542812

    pChAT is a splice variant of a peripheral type encoded alternatively by the gene for choline acetyltransferase of the common type (cChAT), the enzyme responsible for acetylcholine synthesis. Immunohistochemistry using pChAT antiserum has successfully visualized many known peripheral cholinergic cells, whereas most cChAT antibodies failed to do so. As, however, accumulating evidence indicates that pChAT expression also occurs in various non-cholinergic neurons, we examined possible acetylcholine production by pChAT in rat dorsal root ganglion as a model. The present study indicated that the ganglion neurons possessed pChAT, but never cChAT, mRNA and protein. Our detailed analysis further showed that, despite low enzyme activities of both choline acetyltransferase and acetylcholinesterase, the level of acetylcholine in the ganglion was as high as to that in various brain regions receiving cholinergic innervation. By using immunoprecipitation methods, we here provide evidence that pChAT definitely has enzyme activity enough to supply physiological concentrations of acetylcholine in the ganglion. We propose that pChAT contributes both to acetylcholine neurotransmission in physiologically identified cholinergic cells and to functions yet unknown in non-cholinergic neurons. Thus pChAT provides a new window on the role of neuronal acetylcholine.
    문서 타입:
    Reference
    카탈로그 번호:
    AB144
    제품명:
    Anti-Choline Acetyltransferase Antibody
  • Nicotinic acetylcholine receptor subunit mRNA expression and channel function in medial habenula neurons. 11044729

    Relationships between nicotinic acetylcholine receptor (nAChR) channel function and nAChR subunit mRNA expression were explored in acutely isolated rat medial habenula (MHb) neurons using a combination of whole-cell recording and single cell RT-PCR techniques. Following amplification using subunit-specific primers, subunits could be categorized in one of three ways: (i) present in 95-100% cells: alpha3, alpha4, alpha5, beta2 and beta4; (ii) never present: alpha2; and (iii) sometimes present ( approximately 40% cells): alpha6, alpha7 and beta3. These data imply that alpha2 subunits do not participate in nAChRs on MHb cells, that alpha6, alpha7 and beta3 subunits are not necessary for functional channels but may contribute in some cells, and that nAChRs may require combinations of all or subsets of alpha3, alpha4, alpha5, beta2 and beta4 subunits. Little difference in the patterns of subunit expression between nicotine-sensitive and insensitive cells were revealed based on this qualitative analysis, implying that gene transcription per se may be an insufficient determinant of nAChR channel function. Normalization of nAChR subunit levels to the amount of actin mRNA, however, revealed that cells with functional channels were associated with high levels (>0.78 relative to actin; 11/12 cells) of all of the category (i) subunits: alpha3, alpha4, alpha5, beta2 and beta4. Conversely, one or more of these subunits was always low (0.40 relative to actin) in all cells with no detectable response to nicotine. Thus the formation of functional nAChR channels on MHb cells may require critical levels of several subunit mRNAs.
    문서 타입:
    Reference
    카탈로그 번호:
    MAB305
    제품명:
    Anti-Choline Acetyltransferase Antibody, clone 1E6
  • Acetylcholine and histamine are transmitter candidates in identifiable mechanosensitive neurons of the spider Cupiennius salei: an immunocytochemical study. 8995212

    Histochemical and indirect immunocytochemical techniques were used to search for neuroactive substances and transmitter candidates in identified sensory neurons of two types of cuticular mechanoreceptors in the spider Cupiennius salei Keys.: (1) in lyriform slit-sense organ VS-3 (comprising 7-8 cuticular slits each innervated by 2 bipolar neurons), and (2) in tactile hairs (each supplied by 3 bipolar sensory cells). All neurons are mechanosensitive. A polyclonal antibody against choline acetyltransferase (ChAT) strongly labeled all cell bodies and afferent fibers of both mechanoreceptor types. Western blot analysis using the same antibody against samples of spider sensory hypodermis and against samples from the central nervous system demonstrated a clear band at 65 kDa, corresponding to the molecular mass of ChAT in insects. Moreover, staining for acetylcholine esterase (AChE) revealed AChE activity in one neuron of each mechanoreceptor type. Incubation with a polyclonal antibody against histamine clearly labeled one neuron in each set of sensilla, whereas activity in the remaining one or two cells was near background. All mechanoreceptor preparations treated with a polyclonal antiserum against serotonin tested negative, whereas sections through the central nervous system of the same spiders were clearly labeled for serotonin. The presence of ChAT-like immunoreactivity and AChE implicates acetylcholine as a transmitter candidate in the two mechanoreceptive organs. We assume that histamine serves as a mechanosensory co-transmitter in the central nervous system and may also act at peripheral synapses that exist in these sensilla.
    문서 타입:
    Reference
    카탈로그 번호:
    AB143
    제품명:
    Anti-Choline Acetyltransferase (ChAT) Antibody
  • Release of acetylcholine and GABA, and activity of their synthesizing enzymes in the rat pontine reticular formation. 1686297

    The aim of this study was to obtain neurochemical information on the possible role of acetylcholine (ACh) and gamma-aminobutyric acid (GABA) as neurotransmitters in the pontine reticular formation (PRF). We studied the uptake of labeled choline and GABA, as well as the release of this amino acid and of ACh, in PRF slices of the rat. In addition, choline acetyltransferase, acetylcholinesterase and glutamate decarboxylase activities were assayed in PRF homogenates. The uptake of GABA was strictly Na(+)-dependent, whereas choline uptake was only partially Na(+)-dependent. The release of both ACh and GABA was stimulated by K(+)-depolarization, but only the former was Ca(2+)-dependent. Choline acetyltransferase activity in the PRF was 74% of that in the striatum, whereas acetylcholinesterase activity was considerably lower. Glutamate decarboxylase activity in the PRF was about half that observed in the striatum. These findings support the possibility that both ACh and GABA may act as neurotransmitters in the rat PRF.
    문서 타입:
    Reference
    카탈로그 번호:
    70-600
  • Muscarinic acetylcholine receptor localization and activation effects on ganglion response properties. 20042645

    PURPOSE: The activation and blockade of muscarinic acetylcholine receptors (mAChRs) affects retinal ganglion cell light responses and firing rates. This study was undertaken to identify the full complement of mAChRs expressed in the rabbit retina and to assess mAChR distribution and the functional effects of mAChR activation and blockade on retinal response properties. METHODS: RT-PCR, Western blot analysis, and immunohistochemistry were used to identify the complement and distribution of mAChRs in the rabbit retina. Extracellular electrophysiology was used to determine the effects of the activation or blockade of mAChRs on ganglion cell response properties. RESULTS: RT-PCR of whole neural retina resulted in the amplification of mRNA transcripts for the m1 to m5 mAChR subtypes. Western blot and immunohistochemical analyses confirmed that all five mAChR subtypes were expressed by subpopulations of bipolar, amacrine, and ganglion cells in the rabbit retina, including subsets of cells in cholinergic and glycinergic circuits. Nonspecific muscarinic activation and blockade resulted in the class-specific modulation of maintained ganglion cell firing rates and light responses. CONCLUSIONS: The expression of mAChR subtypes on subsets of bipolar, amacrine, and ganglion cells provides a substrate for both enhancement and suppression of retinal responses via activation by cholinergic agents. Thus, the muscarinic cholinergic system in the retina may contribute to the modulation of complex stimuli. Understanding the distribution and function of mAChRs in the retina has the potential to provide important insights into the visual changes that are caused by decreased ACh in the retinas of Alzheimer\'s patients and the potential visual effects of anticholinergic treatments for ocular diseases.
    문서 타입:
    Reference
    카탈로그 번호:
    Multiple
    제품명:
    Multiple
  • Acetylcholine as an age-dependent non-neuronal source in the heart. 20510655

    In the heart, acetylcholine (ACh) slows pacemaker activity, depresses contractility and slows conduction in the atrioventricular node. Beside these cardiovascular effects, ACh has also been associated with an anti-inflammatory and anti-apoptotic pathway. There is no evidence for ACh synthesis and excretion in other cell types than neuronal cells in the heart. Therefore, this study investigates whether cardiomyocytes are able to synthesize, transport and excrete ACh in the heart. We chose a rat model of different aged rats (neonatal, 6-8 week = young, 20-24 month = old). By real-time PCR, Western blot and immunofluorescence experiments we could demonstrate that adult, but not neonatal cardiomyocytes, express the choline acetyltransferase (ChAT). The expression level of ChAT is down-regulated in old cardiomyocytes. Furthermore, we found that young and old cardiomyocytes express the ACh transport proteins choline transporter-1 (CHT-1) and the vesicular acetylcholine transporter (VAChT). The amount of ACh excretion detected by high performance liquid chromatography (HPLC) is significantly down-regulated in old cardiomyocytes. Bromo-acetylcholine (BrACh), a specific ChAT inhibitor, significantly decreased ACh concentrations in cardiomyocyte supernatants demonstrating that ChAT is the main ACh synthesizing enzyme in cardiomyocytes. In conclusion, we could demonstrate that adult, but not neonatal, cardiomyocytes are able to synthesize, transport and excrete ACh in the rat heart. The expression level of ChAT and the ACh excretion amount are significantly down-regulated in old cardiomyocytes. This finding may provide new physiological/pathological aspects in the communication between cardiomyocytes and other cell types in the myocardium, e.g. fibrocytes, neurocytes or endothelial cells.
    문서 타입:
    Reference
    카탈로그 번호:
    AB5042
    제품명:
    Anti-Choline Acetyltransferase Antibody
  • Alpha7 nicotinic acetylcholine receptor expression by vascular smooth muscle cells facilitates the deposition of Abeta peptides and promotes cerebrovascular amyloid angio ... 18708033

    Deposition of beta-amyloid (Abeta) peptides in the walls of brain blood vessels, cerebral amyloid angiopathy (CAA), is common in patients with Alzheimer's disease (AD). Previous studies have demonstrated Abeta peptide deposition among vascular smooth muscle cells (VSMCs), but the source of the Abeta and basis for its selective deposition in VSMCs are unknown. In the present study, we examined the deposition patterns of Abeta peptides, Abeta40 and Abeta42, within the cerebrovasculature of AD and control patients using single- and double-label immunohistochemistry. Abeta40 and Abeta42 were abundant in VSMCs, especially in leptomeningeal arteries and their initial cortical branches; in later-stage AD brains this pattern extended into the microvasculature. Abeta peptide deposition was linked to loss of VSMC viability. Perivascular leak clouds of Abeta-positive material were associated primarily with arterioles. By contrast, control brains possessed far fewer Abeta42- and Abeta40-immunopositive blood vessels, with perivascular leak clouds of Abeta-immunopositive material rarely observed. We also demonstrate that VSMCs in brain blood vessels express the alpha7 nicotinic acetylcholine receptor (alpha7nAChR), which has high binding affinity for Abeta peptides, especially Abeta42. These results suggest that the blood and blood-brain barrier permeability provide a major source of the Abeta peptides that gradually deposit in brain VSMCs, and the presence and abundance of the alpha7nAChR on VSMCs may facilitate the selective accumulation of Abeta peptides in these cells.
    문서 타입:
    Reference
    카탈로그 번호:
    AB5078P
    제품명:
    Anti-Beta-Amyloid 1-42 Antibody
  • α7 nicotinic acetylcholine receptor agonist PNU-282987 attenuates early brain injury in a perforation model of subarachnoid hemorrhage in rats. 21960575

    Early brain injury is an important pathological process after subarachnoid hemorrhage (SAH). The goal of this study was to evaluate whether the α7 nicotinic acetylcholine receptor (α7nAChR) agonist PNU-282987 attenuates early brain injury after SAH and whether α7nAChR stimulation is associated with down-regulation of caspase activity via phosphatidylinositol 3-kinase-Akt signaling.The perforation model of SAH was performed, and neurological score, body weight loss, and brain water content were evaluated 24 and 72 hours after surgery. Western blot and immunohistochemistry were used for quantification and localization of phosphorylated Akt and cleaved caspase 3. Neuronal cell death was quantified with TUNEL staining. α7nAChR antagonist methylcaconitine and phosphatidylinositol 3-kinase inhibitor wortmannin were used to manipulate the proposed pathway, and results were quantified with Western blot.PNU-282987 improved neurological deficits both 24 and 72 hours after surgery and reduced brain water content in left hemispheres 24 hours after surgery. PNU-282987 significantly increased phosphorylated Akt levels and significantly decreased cleaved caspase 3 levels in ipsilateral hemispheres after SAH. Methylcaconitine and wortmannin reversed effects of treatment. Phosphorylated Akt and cleaved caspase 3 were colocalized to neurons in the ipsilateral basal cortex. Phosphorylated Akt was mainly localized in TUNEL-negative cells. PNU-282987 significantly reduced neuronal cell death in the ipsilateral basal cortex.α7nAChR stimulation decreased neuronal cell death and brain edema and improved neurological status in a rat perforation model of SAH. α7nAChR stimulation is associated with increasing phosphorylation of Akt and decreasing cleaved caspase 3 levels in neurons.
    문서 타입:
    Reference
    카탈로그 번호:
    MAB377
    제품명:
    Anti-NeuN Antibody, clone A60