Plasma concentration of acetylcholine in young women

doi:10.1016/0304-3940(87)90478-2

Neuroscience Letters

Volume 80, Issue 3, 5 October 1987, Pages 339-342

https://doi.org/10.1016/0304-3940(87)90478-2 Get rights and content

Abstract

A sensitive and specific radioimmunoassay was applied to the determination of acetylcholine (ACh) in plasma. The concentration of ACh in plasma sampled from 32 young women was 456.1 ± 53.1 (mean ± S.E.M.) pg/ml. No significant correlations were observed between plasma concentration of ACh and acetylcholinesterase (AChE) activity, or gonadal hormones. These data demonstrate that an amount of ACh measurable by radioimmunoassay is present in plasma and plasma ACh is not regulated by AChE activity and the menstrual cycle in young women. The origin and physiological as well as pathophysiological significance of ACh in plasma remain to be clarified.

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Cited by (37)

Determination of non-neuronal acetylcholine in human peripheral blood mononuclear cells by use of hydrophilic interaction ultra-performance liquid chromatography-tandem mass spectrometry
2016, Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
Citation Excerpt :
Although the AChE mRNA levels also correlated with VAChT mRNA levels (Spearman r = 0.68, P < 0.01) (Fig. 4A–C), no such correlations were noted between plasma AChE activity and intracellular AChE activity (Spearman r = 0.12, P = 0.535) in volunteers (Fig. 4D). Kawashima detected and measured ACh concentrations in human plasma as about 0.4 ng/mL [8]. However, with our more sensitive UPLC–MS/MS detection method, we found that human plasma lacks ACh, regardless of our addition of adequate AChE inhibitor or not (data not shown).
Cholinergic components in non-neuronal tissues and cells are proposed as important in maintaining cellular proliferation and immune homeostasis. However, direct quantification of non-neuronal acetylcholine (ACh) in cells has been inefficient. Therefore, we developed a stable method for determination of intracellular ACh.
We used ultra performance liquid chromatography-tandem mass spectrometry (UPLC–MS/MS) with Waters CORTECS chromatographic columns to measure the intracellular ACh in human peripheral blood mononuclear cells (PBMCs). The presence of ACh was validated by RT-qPCR of mRNAs of cholinergic components.
This method successfully separated ACh from iso-ACh with highly sensitive precursor/product ion transitions and allowed a faster chromatography run time within 3.5 min. The detection limit of intracellular ACh was 0.005 ng/10⁶ PBMCs. Intra-assay and inter-assay coefficient variations were all <7.0%. Mean recoveries in the samples were between 93.20% and 104.73%. Here, intracellular ACh was stable under multiple storage conditions, partly attributable to mutually stable relationships among cholinergic components. This method was successfully applied in a stroke study and revealed activation of the stroke-induced cholinergic anti-inflammatory pathway.
This method allows direct determination of intracellular ACh in various tissues. Evidences of cholinergic activity linking both the nervous system and non-neuronal system can be profiled by assessing ACh.
Non-neuronal cholinergic system in regulation of immune function with a focus on α7 nAChRs
2015, International Immunopharmacology
Citation Excerpt :
Then in 1987, using a sensitive and specific radioimmunoassay (RIA) for ACh [26] and paraoxon, an instantaneously active AChE inhibitor, we detected 456 ± 53 pg/ml of ACh in the plasma of young women (n = 32) [27]. We then subsequently confirmed the presence of ACh in blood and plasma from various mammalian species, including humans (Table 1) [27–32]. The ACh levels in bovine blood were about 40 times higher than in human, and the levels in equine blood were about 10 times higher.
In 1929, Dale and Dudley described the first reported natural occurrence of acetylcholine (ACh) in an animal’s body. They identified this ACh in the spleens of horses and oxen, which we now know suggests possible involvement of ACh in the regulation of lymphocyte activity and immune function. However, the source and function of splenic ACh were left unexplored for several decades. Recent studies on the source of ACh in the blood revealed ACh synthesis catalyzed by choline acetyltransferase (ChAT) in CD4⁺ T cells. T and B cells, macrophages and dendritic cells (DCs) all express all five muscarinic ACh receptor subtypes (mAChRs) and several subtypes of nicotinic AChRs (nAChRs), including α7 nAChRs. Stimulation of these mAChRs and nAChRs by their respective agonists causes functional and biochemical changes in the cells. Using AChR knockout mice, we found that M₁/M₅ mAChR signaling up-regulates IgG₁ and pro-inflammatory cytokine production, while α7 nAChR signaling has the opposite effect. These findings suggest that ACh synthesized by T cells acts in an autocrine/paracrine fashion at AChRs on various immune cells to modulate immune function. In addition, an endogenous allosteric and/or orthosteric α7 nAChR ligand, SLURP-1, facilitates functional development of T cells and increases ACh synthesis via up-regulation of ChAT mRNA expression. SLURP-1 is expressed in CD205⁺ DCs residing in the tonsil in close proximity to T cells, macrophages and B cells. Collectively, these findings suggest that ACh released from T cells along with SLURP-1 regulates cytokine production by activating α7 nAChRs on various immune cells, thereby facilitating T cell development and/or differentiation, leading to immune modulation.
Critical roles of acetylcholine and the muscarinic and nicotinic acetylcholine receptors in the regulation of immune function
2012, Life Sciences
Citation Excerpt :
However, no detectable amount of ACh was found in either the PMNL fraction, which consists of mainly neutrophils, or the red cell fraction. The remaining portion of blood ACh appears to be present largely in plasma, because we previously found a plasma ACh level of 456 ± 53 (mean ± SEM) pg/ml (corresponding to 36% of the total blood ACh content) in 32 young women (Kawashima et al., 1987). The findings suggest that ACh in the blood originates primarily from lymphocytes.
Lymphocytes express both muscarinic and nicotinic acetylcholine (ACh) receptors (mAChRs and nAChRs, respectively), and stimulation of mAChRs and nAChRs produces various biochemical and functional changes. Although it has been postulated that parasympathetic cholinergic nerves directly innervate immune cells, no evidence has supported this hypothesis. We measured ACh in the blood of various animal species and determined its localization in T cells using a sensitive and specific radioimmunoassay. Furthermore, we showed that T cells express choline acetyltransferase (ChAT), an ACh synthesizing enzyme. Immunological T cell activation enhances ACh synthesis through the up-regulation of ChAT expression, suggesting lymphocytic cholinergic activity is related to immunological activity. Most immune cells such as T cells, B cells, and monocytes express all five subtypes of mAChRs (M₁–M₅), and various subunits of the nAChR, such as α3, α5, α7, α9, and α10. Studies on serum antibody production in M₁ and M₅ combined mAChR gene knockout (KO) mice immunized with ovalbumin (OVA) revealed that M₁/M₅ mAChRs up-regulate TNF-α, IFN-γ and IL-6 production in spleen cells, leading to an elevation of serum anti-OVA specific IgG₁. In contrast, studies of nAChR α7 subunit gene KO mice immunized with OVA show that α7 nAChRs down-regulate these proinflammatory cytokines, thereby leading to a reduction of anti-OVA specific IgG₁. Taken together, these findings demonstrate that both mAChRs and nAChRs modulate production of cytokines, such as TNF-α, resulting in a modification of antibody production. These findings support the notion that a non-neuronal cholinergic system is involved in the regulation of immune cell function.
Angiogenic activity of nicotinic acetylcholine receptors: Implications in tobacco-related vascular diseases
2009, Pharmacology and Therapeutics
Cigarette smoking bears a strong etiological association with many neovascularization-related diseases like cancer, cardiovascular disease and macular degeneration. Although cigarette smoke is a complex mixture of many compounds, nicotine is the major active and addictive component of tobacco. Recent studies have shown that nicotine can enhance angiogenesis and arteriogenesis in several experimental systems and animal models. The pro-angiogenic activity of nicotine is mediated by nicotinic acetylcholine receptors, which have been found to be expressed on several types of cells in the vasculature like endothelial cells, smooth muscle cells and immune cells. The present review summarizes the pro-angiogenic activity of nicotine in neoplastic and non-neoplastic disease. The present article focuses on the role of nAChRs, particularly α7-nAChR in mediating the pro-angiogenic effects of nicotine. The expression patterns of nAChRs on various components of the vasculature are discussed. The complex signaling pathways underlying the angiogenic effect of nAChRs are described. The review also takes a look at the therapeutic potential of nAChR agonists and antagonists in angiogenesis-related diseases. More basic research as well as patient-oriented clinical studies is needed to firmly establish the clinical potential of nAChR ligands in angiogenesis-based therapies. Also the side effects of targeting nAChRs remain to be established in patients. The development of selective nAChR agonists and antagonists with improved specificity may represent novel therapeutic regimens in the treatment of angiogenesis-related diseases.
Decreased acetylcholine content and choline acetyltransferase mRNA expression in circulating mononuclear leukocytes and lymphoid organs of the spontaneously hypertensive rat
2001, Life Sciences
It has been confirmed that the neurotransmitter acetylcholine (ACh) is present in blood; it is synthesized in T-lymphocytes by choline acetyltransferase (ChAT) and released upon T-lymphocyte activation. Both muscarinic and nicotinic ACh receptors have been identified on lymphocytes isolated from thymus, lymph node, spleen and blood, and their stimulation by muscarinic and nicotinic agonists elicits a variety of functional and biochemical effects, providing a strong argument that ACh synthesized and released from T-lymphocytes acts as an autocrine and/or paracrine factor regulating immune function. In the present study, we compared ACh levels in the blood, circulating mononuclear leukocytes (MNLs), thymus and spleen of spontaneously hypertensive rats (SHRs), which exhibit immune deficiencies related to the emergence of natural thymocytotoxic autoantibody, age-related decline of T-cell function and morphological changes in immune organs, with ACh levels in age-matched, normotensive Wistar Kyoto rats. In each case, ACh levels in 5-, 10- and 20-week-old SHRs were significantly lower than in WKYs. ChAT mRNA expression in MNLs was also significantly depressed in the SHRs. These results suggest that diminished synthesis and release of ACh from MNLs into blood and lymphoid organs likely reflects an immune deficiency related to T-cell dysfunction.
Extraneuronal cholinergic system in lymphocytes
2000, Pharmacology and Therapeutics
Acetylcholine (ACh) is well known as a neurotransmitter in both the central and peripheral nervous systems in mammalian species. Both muscarinic and nicotinic ACh receptors have been identified in lymphocytes isolated from thymus, lymph node, spleen, and peripheral blood, and their stimulation by muscarinic and nicotinic agonists elicits a variety of functional and biochemical effects. On the basis of these findings, it has been postulated that the parasympathetic nervous system may play a role in immune-neurohumoral crosstalk. However, ACh present in the blood of several species has been localized to lymphocytes from various origins using radioimmunoassay. Moreover, using Northern blots or reverse transcription-polymerase chain reaction, expression of choline acetyltransferase, an ACh synthesizing enzyme, has been identified in human blood mononuclear leukocytes, human leukemic T-cell lines, and rat lymphocytes. Stimulation of T-lymphocytes with phytohemagglutinin activates the lymphoid cholinergic system, as evidenced by increased synthesis and release of ACh, increased acetylcholinesterase activity, and the increased expression of mRNA encoding choline acetyltransferase and ACh receptors. The observation that muscarinic receptor stimulation by ACh or agonists increases in [Ca²+]_i and up-regulates c-fos expression strongly argues that ACh synthesized and released from T-lymphocytes acts as an autocrine and/or paracrine factor regulating immune function. In summary, these data present a compelling picture in which immune function is not only regulated by the cytokine system, but is also under the control of an independent, lymphoid cholinergic system.

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Plasma concentration of acetylcholine in young women

Abstract

Biochem. Pharmacol.

J. Chromatogr.

J. Pharmacol. Methods

The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine

Nature (London)

Plasma catecholamines and essential hypertension; an analytical review

Hypertension

Acetylcholine and choline in human plasma and red blood cells: a gas chromatograph mass spectrometric evaluation