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Updated: Dec 27, 2025

An Intestine/Liver Microphysiological System for Drug Pharmacokinetic and Toxicological Assessment
Published on: December 3, 2020
Identification of the Uptake Transporter Responsible for Distribution of Acotiamide into Stomach Tissue
Masamichi Hirayama1,2, Yusuke Hoshino1, Kazuyoshi Yoshii1
1Toxicology & Pharmacokinetics Research, Central Research Laboratories, Zeria Pharmaceutical Corporation Ltd., Saitama 360-0111, Japan.
Abstract:
The acetylcholinesterase inhibitor, acotiamide, improves gastric motility and is clinically used to treat functional dyspepsia. The present study aimed to identify the transporters involved in the distribution of acotiamide in stomach tissue. Acotiamide uptake by the gastric cancer-derived model cell line, Hs746 T, was Na+- and pH-independent. The initial uptake velocity of acotiamide was saturable with increasing concentrations of acotiamide and was inhibited by selective serotonin reuptake inhibitors, which are potent inhibitors of the plasma membrane monoamine transporter (PMAT). The uptake of acotiamide by PMAT gene-transfected HEK293 cells was saturable, with similar Km (197.9 μM) values to those of uptake by Hs 746T cells (106 μM). Moreover, immunoreactivity of PMAT was found in the gastric smooth muscle and vascular endothelial cells. These results suggest that PMAT contributes to the distribution of acotiamide in the stomach, where it exerts its pharmacological effects.
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