Avian gut experiments: an alternative approach for teaching the properties of intestinal smooth muscles.

Experiments on isolated mammalian gut are essential components of the physiology curriculum worldwide. Over the years, these routine experiments have been largely replaced by simulation modules, to reduce the euthanization of animals for understanding established facts and mechanisms in gut physiology. However, a medical undergraduate needs hands-on training to handle a living tissue to have a better understanding of physiology. The present sourcebook update describes the use of avian gut, which is usually discarded in abattoirs, as an effective replacement of mammalian gut to understand basic gut smooth muscle physiology. The avian gut can be used to study the effect of various drugs and ions as used in mammalian gut experiments. The experiment protocol described in the update can be performed by students of basic sciences and medical students using minimal laboratory set up and at low cost, producing results comparable to mammalian gut experiments. Ethical permissions may not be necessary; however, the disposal of tissue waste has to follow proper guidelines.

Acute Exposure to Bisphenol S Decreases In Vitro Right Atrial Contractility in Rats.

AIM/OBJECTIVE: Bisphenols are widely used in the manufacturing of polycarbonate material and epoxy resins which constitute the essential component of plastic. Bisphenol A (BPA) has been reported to produce toxicity on organs in both animal and human studies. Therefore, plastic manufacturers are replacing BPA with other analogues that are considered to be safe, and BPA-free products are now available in the market. However, some studies have reported that bisphenol-S (BPS) also possesses toxic properties. It has been reported to depress ventricular contraction as well as produce ventricular arrhythmia on acute exposure. The present study was performed to examine the effect of BPS on in vitro spontaneously-beating right atria in rats. METHODS: In the present study, in vitro spontaneous contractions of right atria obtained from adult female rats of the Wistar strain were recorded. The atria were exposed to BPS (10-6-10 mM) and its effects on atrial contractions were recorded in the form of cumulative-concentration response with and without administration of antagonists namely atropine, L-NAME, and methylene blue. RESULTS: BPS decreased the rate as well as the force of atrial contractions. The changes produced in the rate and force of atrial contractions were not attributed to ethanol, which was used to prepare BPS solutions. The decrease in right atrial contractility produced by BPS was blocked by L-NAME; however, atropine and methylene blue were not able to antagonize the effects of BPS on atria. CONCLUSIONS: The present study indicates the involvement of NO-dependent but cGMP independent pathway responsible for BPS-induced cardio-toxicity.