The effect of DA-9701 on 5-hydroxytryptamine-induced contraction of feline esophageal smooth muscle cells

• Published in: Molecules (Basel, Switzerland) Vol. 19; no. 4; pp. 5135 - 5149
• Main Authors: Oh, Kyung Hoon, Nam, Yoonjin, Jeong, Ji Hoon, Kim, In Kyeom, Sohn, Uy Dong
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22-04-2014; MDPI
• Subjects: 5-hydroxytryptamine; Animals; Antibodies; Blood platelets; Cats; Corydalis Tuber; DA-9701; Esophagus; Esophagus - cytology; Esophagus - drug effects; Esophagus - metabolism; feline esophageal smooth muscle; Gastrointestinal Agents - pharmacology; Gene Expression Regulation; GTP-Binding Proteins - genetics; GTP-Binding Proteins - metabolism; Humans; Kinases; Ligands; MLC20; Motility; Muscle contraction; Muscle Contraction - drug effects; Muscle Contraction - genetics; Muscle, Smooth - cytology; Muscle, Smooth - drug effects; Muscle, Smooth - metabolism; Myocytes, Smooth Muscle - cytology; Myocytes, Smooth Muscle - drug effects; Myocytes, Smooth Muscle - metabolism; Myosin Light Chains - genetics; Myosin Light Chains - metabolism; Myosin-Light-Chain Kinase - genetics; Myosin-Light-Chain Kinase - metabolism; Nervous system; Pharbitidis Semen; Pharmacology; Phosphorylation; Plant Preparations - pharmacology; Protein Binding; Proteins; Receptors, Serotonin - genetics; Receptors, Serotonin - metabolism; Serotonin; Serotonin - metabolism; Serotonin - pharmacology; Signal Transduction; Smooth muscle; Type C Phospholipases - genetics; Type C Phospholipases - metabolism
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules19045135

Serotonin, or 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter found in blood platelets, the gastrointestinal (GI) tract, and the central nervous system (CNS) of animals and humans. The signaling pathways of 5-hydroxytryptamine (5-HT)-induced contractions in cat esophageal smooth muscle cell (ESMC)s have been identified, but the downstream components of the 5-HT signaling pathway remain unclear. DA-9701 is the standardized extract of the Pharbitis nil Choisy seed (Pharbitidis Semen, Convolvulaceae) and the root of Corydalis yahusuo W.T. Wang (Corydalis Tuber, Papaveraceae). DA-9701 is known to have strong gastroprokinetic effects and a good safety profile. In this study, we investigated the 5-HT signaling pathway at the G-protein level, and we explored the mechanisms by which DA-9701 induces smooth muscle contraction. Freshly isolated smooth muscle cells were harvested from the feline esophagus, and cells were permeabilized to measure their length. 5-HT produced esophageal smooth muscle contractions in a dose-dependent manner. Furthermore, 5-HT produced a relatively long-acting contraction. 5-HT binds to the 5-HT2, 5-HT3 and 5-HT4 receptors to induce smooth muscle contraction in feline ESMCs. These receptors, which are located in esophageal smooth muscle, are coupled to Gαq, Gαo and Gαs. These G proteins activate PLC, which leads to Ca2+/calmodulin-dependent MLCK activation, resulting in MLC20 phosphorylation and cell contraction. Conversely, DA-9701 inhibits 5-HT-induced contraction by inhibiting MLC20 phosphorylation.