Do atropine and diphenhydramine, two anti-cholinergic drugs, interact to affect Daphnia magna heart rate?

The Daphnia magna is a type of water flea that is commonly utilized to test pharmacological and physiological responses. In this project, two common pharmaceuticals, Atropine and Diphenhydramine, will be utilized to test the effects that these drugs have on the heart rate of the Daphnia. Atropine and Diphenhydramine are classified as anticholinergic drugs, meaning they act on the parasympathetic nervous system to block the effects that the parasympathetic nervous system would exhibit. As it relates to this project, the parasympathetic nervous system would normally act to slow heart rate, but by utilizing an anticholinergic drug, the opposite response occurs, meaning heart rate is increased. Diphenhydramine (the primary ingredient in Benadryl) is also classified as an antihistamine and is most commonly utilized for its antihistamine purposes. The effects of Atropine on the Daphnia heart rate are not well known, and the effects of Diphenhydramine on the Daphnia heart has not been studied. Given that it is considered a hazard to take more than one anti-cholinergic drug concurrently, I will investigate the dangers of taking these drugs concurrently. The ultimate goal of this project is to determine whether the Daphnia is a reliable testing organism for anti-cholinergic drugs. This is significant, because the pharmaceutical industry is booming, so it is crucial to identify reliable testing organisms for the future synthesis of pharmaceuticals.