scholarly journals Accumulation and metabolism of Ins(1,4,5)P3 and Ins(1,3,4,5)P4 in muscarinic-receptor-stimulated SH-SY5Y neuroblastoma cells

1991 ◽  
Vol 273 (3) ◽  
pp. 791-794 ◽  
Author(s):  
D G Lambert ◽  
R A J Challiss ◽  
S R Nahorski
Keyword(s):  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Neuroblastoma Cells ◽  
Stimulation Of ◽  
Related Increase

Stimulation of M3 muscarinic receptors expressed by SH-SY5Y cells induced a dose- and time-related increase in the mass of Ins(1,4,5)P3 (basal 38.3 +/- 5.8 pmol/mg of protein) and Ins(1,3,4,5)P4 (basal 6.1 +/- 1.2 pmol/mg of protein). Comparison of radioreceptor mass assays with [3H]inositol labelling showed higher-fold stimulations with the former protocol. The later accumulation of Ins(1,4,5)P3 and Ins(1,3,4,5)P4 mass was dependent upon extracellular Ca2+.

scholarly journals Characterization of Prejunctional Muscarinic Receptors: Effects on the Release of VIP and Functional Responses and Receptor Expression in the Ovine Submandibular Gland

2009 ◽  
Vol 2009 ◽  
pp. 1-6
Author(s):  
Anders T. Ryberg ◽  
Ondrej Soukup ◽  
Gunnar Tobin
Keyword(s):  
Electrical Stimulation ◽  
Submandibular Gland ◽  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Receptor Expression ◽  
Receptor Subtypes ◽  
Chorda Tympani Nerve ◽  
Functional Responses ◽  
Stimulation Of

In the in vivo experiments on anaesthetized sheep, it was presently examined whether muscarinic receptor antagonists with diverse selectivity affect the release of VIP in response to electrical stimulation of the parasympathetic chorda tympanic nerve differently, and if the changes in the release could be associated to altered secretory and vasodilator responses. The location of the muscarinic receptor subtypes was examined also. In the experiments, blood was collected out of the submandibular venous drainage before and during electrical stimulation of chorda tympani nerve in the absence and presence either of pirenzepine or methoctramine. While metchoctramine increased the output of protein, pirenzepine inhibited flow of saliva and increased protein output, vasodilatation, and VIP output. In morphological examinations, the inhibitory muscarinic M4 receptor occurred interacinarily in the gland. It is concluded that prejunctional muscarinic receptors, most likely of the M4 subtype, exert inhibitory modulation of the parasympathetic release of VIP in the ovine submandibular gland.

scholarly journals Functional Characterization of Muscarinic Receptors in Human Schwann Cells

2020 ◽  
Vol 21 (18) ◽  
pp. 6666
Author(s):  
Roberta Piovesana ◽  
Alessandro Faroni ◽  
Ada Maria Tata ◽  
Adam J. Reid
Keyword(s):  
Cell Proliferation ◽  
Schwann Cells ◽  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Functional Characterization ◽  
Receptor Subtypes ◽  
Muscarinic Receptor Subtypes ◽  
Selective Stimulation ◽  
Stimulation Of

Functional characterization of muscarinic cholinergic receptors in myelinating glial cells has been well described both in central and peripheral nervous system. Rat Schwann cells (SCs) express different muscarinic receptor subtypes with the prevalence of the M2 subtype. The selective stimulation of this receptor subtype inhibits SC proliferation, improving their differentiation towards myelinating phenotype. In this work, we describe for the first time that human SCs are cholinoceptive as they express several muscarinic receptor subtypes and, as for rat SCs, M2 receptor is one of the most abundant. Human SCs, isolated from adult nerves, were cultured in vitro and stimulated with M2 muscarinic agonist arecaidine propargyl ester (APE). Similarly to that observed in rat, M2 receptor activation causes a decreased cell proliferation and promotes SC differentiation as suggested by increased Egr2 expression with an improved spindle-like shape cell morphology. Conversely, the non-selective stimulation of muscarinic receptors appears to promote cell proliferation with a reduction of SC average cell diameter. The data obtained demonstrate that human SCs are cholinoceptive and that human cultured SCs may represent an interesting tool to understand their physiology and increase the knowledge on how the cholinergic stimulation may contribute to address human SC development in normal and pathological conditions.

scholarly journals Pertussis toxin does not inhibit muscarinic-receptor-mediated phosphoinositide hydrolysis or calcium mobilization

1985 ◽  
Vol 227 (3) ◽  
pp. 933-937 ◽  
Author(s):  
S B Masters ◽  
M W Martin ◽  
T K Harden ◽  
J H Brown
Keyword(s):  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Pertussis Toxin ◽  
Inositol Phosphate ◽  
Regulatory Protein ◽  
Calcium Mobilization ◽  
Phosphoinositide Hydrolysis ◽  
Heart Cells ◽  
Chick Heart ◽  
Stimulation Of

Pertussis toxin was used to examine the role of the inhibitory guanine nucleotide regulatory protein, Ni, in muscarinic-receptor-mediated stimulation of phosphoinositide turnover and calcium mobilization. In cultured chick heart cells, pertussis-toxin treatment inhibited muscarinic-receptor-mediated attenuation of isoprenaline-stimulated cyclic AMP accumulation. This finding is consistent with the proposal that pertussis toxin blocks the capacity of Ni to couple muscarinic receptors to adenylate cyclase. In contrast, treatment of chick heart cells or 1321N1 human astrocytoma cells with pertussis toxin did not block muscarinic-receptor-mediated stimulation of phosphoinositide hydrolysis, as measured by [3H]inositol phosphate accumulation in the presence of Li+. Pertussis-toxin treatment also had little effect on basal and muscarinic-receptor-stimulated phosphatidylinositol synthesis, as measured by the incorporation of [3H]inositol into phosphatidylinositol. Activation of muscarinic receptors also enhances the rate of unidirectional 45Ca2+ efflux in 1321N1 cells; this response, like phosphoinositide hydrolysis, was not prevented by pertussis-toxin treatment. Our data suggest that muscarinic receptors are not coupled to phosphoinositide hydrolysis or calcium mobilization through Ni.

scholarly journals Imaging Muscarinic Cholinergic Receptors in Human Brain in vivo with SPECT, [123I]4-Iododexetimide, and [123I]4-Iodolevetimide

1992 ◽  
Vol 12 (4) ◽  
pp. 562-570 ◽  
Author(s):  
Hans W. Müller-Gärtner ◽  
Alan A. Wilson ◽  
Robert F. Dannals ◽  
Henry N. Wagner ◽  
J. James Frost
Keyword(s):  
Human Brain ◽  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Acetylcholine Receptors ◽  
Brain Regions ◽  
Muscarinic Acetylcholine Receptors ◽  
Emission Computed Tomography ◽  
Nonspecific Binding ◽  
Muscarinic Acetylcholine

A method to image muscarinic acetylcholine receptors (muscarinic receptors) noninvasively in human brain in vivo was developed using [123I]4-iododexetimide ([123I]IDex), [123I]4-iodolevetimide ([123I]ILev), and single photon emission computed tomography (SPECT). [123I]IDex is a high-affinity muscarinic receptor antagonist. [123I]ILev is its pharmacologically inactive enantiomer and measures nonspecific binding of [123I]IDex in vitro. Regional brain activity after tracer injection was measured in four young normal volunteers for 24 h. Regional [123I]IDex and [123I]ILev activities were correlated early after injection, but not after 1.5 h. [123I]IDex activity increased over 7–12 h in neocortex, neostriatum, and thalamus, but decreased immediately after the injection peak in cerebellum. [123I]IDex activity was highest in neostriatum, followed in rank order by neocortex, thalamus, and cerebellum. [123I]IDex activity correlated with muscarinic receptor concentrations in matching brain regions. In contrast, [123I]ILev activity decreased immediately after the injection peak in all brain regions and did not correspond to muscarinic receptor concentrations. [123I]IDex activity in neocortex and neostriatum during equilibrium was six to seven times higher than [123I]ILev activity. The data demonstrate that [123I]IDex binds specifically to muscarinic receptors in vivo, whereas [123I]ILev represents the nonspecific part of [123I]IDex binding. Subtraction of [123I]ILev from [123I]IDex images on a pixel-by-pixel basis therefore reflects specific [123I]IDex binding to muscarinic receptors. Owing to its high specific binding, [123I]IDex has the potential to measure small changes in muscarinic receptor characteristics in vivo with SPECT. The use of stereoisomerism directly to measure nonspecific binding of [123I]IDex in vivo may reduce complexity in modeling approaches to muscarinic acetylcholine receptors in human brain.

Sign in / Sign up

Export Citation Format

Share Document