Related Experiment Video
Updated: Aug 18, 2026

In vitro Measurements of Tracheal Constriction Using Mice
Published on: June 25, 2012
Polyspecific cation transporters mediate luminal release of acetylcholine from bronchial epithelium
Katrin Susanne Lips1, Christopher Volk, Bernhard Matthias Schmitt
1Institute of Anatomy and Cell Biology, Justus-Liebig-University, Giessen, Germany.
Abstract:
In airway epithelia, non-neuronal cholinergic regulations have been described; however, the route for acetylcholine (ACh) release has not been verified. To investigate whether organic cation transporters (OCTs) serve this function, we studied the expression of OCTs in airway epithelia and their capability to translocate ACh. Using immunohistochemistry in rats and humans, OCT1, OCT2, and OCT3 were localized to the luminal membrane of ciliated epithelial cells. In humans, OCT2 showed the strongest expression in the luminal membrane. We expressed the OCT isoforms in oocytes of Xenopus laevis and measured uptake and efflux of ACh. Tracer flux measurements showed that ACh is transported by OCT1 and OCT2 but not by OCT3. Two-electrode-voltage-clamp measurements revealed that OCT2 mediates electrogenic uptake and efflux of ACh. For ACh uptake by human OCT2, a K(M) value of approximately 0.15 mM was determined. At -50 mV, ACh efflux by human OCT2 was trans-inhibited by micromolar concentrations of the inhalational glucocorticoid budesonide, which is used in treatment of asthma (K(i) approximately 2.7 microM). The data show that OCT1 and OCT2 mediate luminal ACh release in human airways and suggest that ACh release is blocked after inhalation of budesonide.
More Related Videos
06:59A Fluorescence-Based Assay of Membrane Potential for High-Throughput Functional Study of Two Endogenous Ion Channels in Two Epithelial Cell Lines
Published on: June 22, 2022
07:40Determining Ciliary Function and Membrane Impermeability of the Pseudostratified Lung Airway Epithelium
Published on: February 21, 2025
Related Concept Videos
Cholinergic Neurons: Neurotransmission
Cholinergic Receptors: Muscarinic
The subtypes M1, M3, and M5 couple with the Gq subunit and activate the phospholipase C (PLC) activity, mobilizing intracellular Ca2+. Activation...
Direct-Acting Cholinergic Agonists: Therapeutic Uses
Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
The direct-acting...
Cholinergic Receptors: Nicotinic
There are two types of nicotinic receptors: neuromuscular (NM/NM/N1) and neuronal (NN/NN/N2). The two families differ based on their location and selectivity to...
Direct-Acting Cholinergic Agonists: Pharmacokinetics