Tartrazine Promotes the Contraction of the Duodenal Visceral Smooth Muscle by Facilitating the Cholinergic Signalling Pathway

Tartrazine (TAZ), a synthetic azo dye, continues to be used widely in the food industry for its bright yellow coloration, despite being restricted in several countries. Chronic exposure to TAZ through contaminated food raises concerns regarding its impact on gastrointestinal physiology. This study investigates the effect of Tartrazine on the contractile function of the small intestinal visceral smooth muscle. Ex vivo recordings of duodenal contractions were obtained using an isotonic transducer (IT-2245) coupled with the RMS Polyrite D data acquisition system. Tartrazine-treated rat duodenal tissues displayed a significant increase in both the amplitude and frequency of spontaneous contractions in a dose dependent manner. To understand the neurogenic basis of this augmentation, the tissues were co-treated with cholinergic agonists (e.g., Acetylcholine) and antagonists such as Atropine (a cholinergic receptor blocker). The enhanced contractility induced by Tartrazine was significantly attenuated by Atropine, indicating a muscarinic receptor-mediated mechanism. The results suggest that Tartrazine augments the contractile activity of duodenal visceral smooth muscle (dVSM) probably by potentiating the cholinergic signalling pathways. This excitatory effect may be due to increased acetylcholine release or enhanced muscarinic receptor sensitivity, ultimately contributing to increased motility upon exposure.