Effect of cholinergic stimulation on free intracellular Ca2+ concentration in human lymphocytes.

Binding of ligand to receptor, in various types of cells, results in changes in calcium concentration, which is an important factor in cellular signal transduction. Lymphocytes receive signals from the parasympathetic nervous system through the cholinergic receptors. Cholinergic receptors mediate response to stimuli through changes of the IP3, or cAMP level and Ca2+ mobilization in various types of cells.

Accumulation of inositol 1,4,5-triphosphate after cholinergic stimulation of human lymphocytes.

The interrelationships between the immune and neurohormonal system are the subject of this work. The formation of inositol 1,4,5-triphosphate (IP3) in response to cholinergic stimulation was studied in the human peripheral blood mononuclear cells (PBMC) and lymphocytes from the lymphoblastoid cell lines Jurkat and Raji. The cells were stimulated with mitogen and then treated with cholinergic agonist-carbachol or nicotine.

Level of inositol-1,4,5-trisphosphate after cholinergic stimulation of human lymphocytes.

The interrelationships between the immune and neurohormonal system are the subject of this work. In this context, the formation of inositol-1,4,5-trisphosphate (IP3) in response to cholinergic stimulation was studied in activated human peripheral blood mononuclear cells (PBMC) and lymphocytes from the lymphoblastoid cell lines Jurkat and Raji. The cells were stimulated with mitogen and then treated with either the cholinergic agonist carbachol or nicotine.

Expression of muscarinic cholinergic receptors on lymphocytes in various subsets of rheumatoid arthritis and their variabilities connected with treatment.

Objective: To investigate muscarinic cholinergic receptors on lymphocytes from various subsets of patients with rheumatoid arthritis (RA).

Methods: The level of muscarinic receptors on peripheral blood lymphocytes from 38 patients with various subsets of RA [5 with inactive, 13 with active RA, 13 with rheumatoid vasculitis and 5 with reactive secondary amyloidosis (RSA)] was determined by the binding studies of specific muscarinic ligand [3H] quinuclidinyl benzilate in comparison to healthy individuals.

Results: Expression of muscarinic cholinergic receptors on lymphocytes in patients with RA was significantly higher (mean 1022; SD +/- 567) compared to healthy individuals (mean 647; SD +/- 170) (p < 0.

Muscarinic cholinergic receptors of rat lymphocytes: effect of antigen stimulation and local brain lesion.

Expression of muscarinic cholinergic receptors (m-AchR) on thymocytes and lymphocytes supports a hypothesis of direct interaction between autonomic innervation and the immune system. Using a muscarinic antagonist, [3H]quinuclidinyl benzilate ([3H]QNB), we revealed different characteristics of m-AchR expression in lymphocytes isolated from the spleen, peripheral blood or thymus of Wistar rats. To further explore the mechanisms controlling m-AchR expression in lymphocytes we have addressed two questions: (i) whether local brain lesions will affect [3H]QNB binding activity of lymphocytes and (ii) whether different antigens will alter m-AchR expression in lymphocytes.

Enhanced responsiveness of rat cardiac myocytes to muscarinic cholinergic stimulation during chemically-induced hypoxia.

In contrast to adrenaline, exogenously administered cholinergic agonist, carbachol have very little effect on the contractility of rat cardiac myocytes, unless its contractile has been increased by adrenergic agonist. This interaction between the muscarinic and adrenergic pathways has been suggested to be the major means by which muscarinic agonist alters adrenergic function. When the cardiac myocytes were incubated in the medium contained the mitochondrial respiratory inhibitor potassium cyanide (chemically-induced hypoxia) the spontaneous contractility was ceased.

Stress-induced changes in muscarinic and beta-adrenergic binding sites on rat thymocytes and lymphocytes.

This study examined the effect of immobilization stress on the expression of muscarinic and beta-adrenergic receptors on thymocytes and lymphocytes obtained from 5-month-old L-E male rats. After 2 h immobilization (acute stress) there was a significant increase in specific binding of [3H]-DHA to beta-adrenergic receptors on thymocytes and on lymphocytes from the blood but not from the spleen, whereas [3H]-QNB binding to muscarinic receptors in those cells was not altered in comparison with the undisturbed control. Chronic immobilization stress (5 days, for 2 h) decreased the [3H]-QNB binding to lymphocytes collected from the spleen and blood but not from thymus; it caused neither a significant change in the 3H-DHA binding to thymocytes nor lymphocytes obtained from the blood and spleen.

Nicotinic receptors of rat lymphocytes during adjuvant polyarthritis.

Resting rat lymphocytes and thymocytes express specific [3H]nicotine binding sites with Kd values 7.5 and 10 nM, respectively. Resting T lymphocytes express 5-7 times as many binding sites (1,500/cell) as do unfractionated thymocytes (250/cell), suggesting that only a subset of thymocytes express nicotinic binding sites.

Neutrophils-induced increase of adenosine triphosphate depletion in rat neonatal cardiac myocytes with impaired energy metabolism.

Isolated, cultured rat neonatal cardiac myocytes were placed in medium supplemented with mitochondrial respiratory inhibitor potassium cyanide which caused a rapid adenosine triphosphate (ATP) depletion. These myocytes with the impaired energy metabolism ("hypoxia-like state") were exposed to unstimulated human neutrophils. Effect of human neutrophils on the myocytes in the "hypoxia-like state" was quantified as a total change in the amount of ATP in cardiac cells.

Increase in the expression of muscarinic cholinergic receptors in isolated, neonatal rat cardiac myocytes treated with potassium cyanide.

On treatment of rat cardiac myocytes with potassium cyanide, ATP content significantly and rapidly decreased in all experimental groups as compared to untreated cells. Contrary to that, the level of muscarinic cholinergic receptors increased significantly, depending on the cyanide concentration. Twenty four hours after removal of cyanide, myocytes exhibited normal levels of both the receptor expression and ATP content.

Cholinergic muscarinic and nicotinic binding by human lymphocytes: differences between peripheral blood cells and cultivated cell lines.

Kinetic and equilibrium studies of [3H]QNB and [3H]nicotine binding to human peripheral blood lymphocytes have been performed. The calculated number of muscarinic binding sites is 6 x 10(4) per cell, and of nicotinic binding sites is 2 x 10(3) per cell. The conditions for routine estimations of muscarinic and nicotinic receptors on human lymphocytes have been established.

Influence of lipid peroxidation and hydrogen peroxide on muscarinic cholinergic receptors and ATP level in rat myocytes and lymphocytes.

Isolated rat neonatal cardiac myocytes and rat lymph-node lymphocytes were treated with Fe2+ cumene hydroperoxide or hydrogen peroxide. The intensity of lipid peroxidation was estimated by measuring production of malondialdehyde (MDA). The level of muscarinic cholinergic receptors was determined by [3H]-QNB binding.

Expression of muscarinic cholinergic receptors during T cell maturation in the thymus.

Thymocytes at various stages of their ontogeny have been studied in relation to their ability to bind [3H]quinuclidinyl benzilate [( 3H]QNB), a specific radioligand of the muscarinic cholinergic receptors. [3H]QNB-specific binding to thymocytes from 15-19-day fetal, newborn and adult thymuses of mice and rats was compared and correlated. Our experiments showed that the kinetics of [3H]QNB binding to thymocytes at 37 degrees C was similar to that of the lymph node lymphocytes (LNL) with maximum after 5 min of incubation and subsequent decrease to 10% of the maximum after 90 min of incubation.

Expression of muscarinic cholinergic receptors on lymphocytes during rheumatoid arthritis.

The level of muscarinic receptors on lymphocytes from rheumatoid arthritis (RA) patients in comparison with healthy individuals was determined by the binding studies of a specific muscarinic ligand [3H]-QNB in the presence of the competitive antagonist atropine. The response to phytohaemagglutinin and the influence of acetylcholine on this process in patients' lymphocytes was also studied. We have found direct correlation among PHA stimulation indices, the level of muscarinic receptors, and the influence of acetylcholine on PHA stimulation indices.

Cultured beating myocytes from neonatal rat heart as a model for the study of muscarinic cholinergic receptors.

Neonatal rat heart myocytes were isolated by digestion of the heart tissue with trypsin. After separation the cells were transferred to plastic cluster dishes where they formed a monolayer culture. After 72 hours in culture the myocytes showed a synchronous contraction and renovation of their membrane structures.

Interference of a synthetic C18 juvenile hormone with mammalian cells in vitro. II. Effects on cell cycle.

Interference of a synthetic C18 juvenile (JH) with the cell cycle of mouse embryo cells (ME-cells) and mouse cells of established cell line (L-cells) was examined. After 3 hour in the medium with JH (20 mg/ml) the cells were transfered to the regular culture medium and labelled with H3-thymidine then incubated for 1 to 48 hours before processing them for autoradiography. The percentage of labelled mitosis was then calculated for all cells samples examined and the labelled mitosis curves were drown and analyzed.

Interference of a synthetic C18 juvenile hormone with mammalian cells in vitro, I. Effects on growth and morphology.

Some of structural and functional analogs of juvenile hormones are now under field examinations as growth inhibitors of some pest-insect populations. So far however very little is known about the possible interference of these compounds with mammalian cells or organisms. In this research the interference of a synthetic preparation of the insect C18 juvenile hormone with mouse embryo fibroblasts (ME-cells) and mouse cells of an established line (L-cells) was studied.

Morphological changes in rat skeletal muscle following reinnervation.

Morphological changes appearing in the course of muscle regeneration after reinnervation of denervated M. soleus (slow) and M. tibialis anterior (fast) rat skeletal muscle were investigated.

In vitro survival and amethopterin effects on the structure of ovarian tissues of the sawfly, Acantholyda nemoralis Thoms.

Whole ovaries of the sawfly, Acantholyda nemoralis Thoms., Tenthredinidae, Hymenoptera, were cultivated by the organ culture technique of Fell in the medium of Jones and Cunningham modified by doubling the contents of salts, sugars and lactalbumin hydrolysate and supplemented with an addition of folate. In the experimental conditions the sawfly ovary survived for several days showing mitoses in the follicular epithelium.