Chocolate Brown HT Inhibits the Contractile Activity of the Small Intestinal Visceral Smooth Muscle in Male Albino Rats

Artificial food dyes, especially azo dyes, have raised health concerns due to their physiological effects on various organ systems. Chocolate Brown HT (also known as E155 or Brown HT), a brown synthetic diazo dye has been widely used for food, cosmetic, and pharmaceutical applications. Till date no such studies have reported the effects of Chocolate Brown HT (CBHT) on the contractile activity of small intestinal visceral smooth muscle (SiVSM). So, this study has been designed to examine the effects of graded doses of CBHT on the contractile activity of SiVSM. To evaluate the effect of CBHT on duodenal visceral smooth muscle (dVSM) contractility, ex vivo recordings of duodenal movements were conducted using an isotonic transducer (IT-2245) connected to an RMS Polyrite D. CBHT inhibits the contractions of small intestine (duodenum) ex vivo as evidenced from the decrease in both the frequency and the amplitude of contractions in a dose-dependent manner. From the results it can be suggested that the CBHT induced inhibition of the contraction of the SiVSM might be due to suppression of the activity of intrinsic cholinergic myenteric efferents and/or facilitation of the activity of nitrergic and/or adrenergic intrinsic myenteric efferents. In conclusion, it can be suggested that CBHT inhibits the contractile activity of SiVSM in dose-dependent manner. Keywords: Chocolate Brown HT, azo dye, contractile activity, small intestinal visceral smooth muscle, intrinsic myenteric efferents.