The specific antidotes are M1 receptor blockers like atropine, scopolamine or diphenhydramine. The active principles are the tropane alkaloids atropine, scopolamine, and hyoscyamine. Some of these alkaloids include atropine, scopolamine, and hyoscyamine. Muscarinic acetylcholine receptors can be blocked by the drugs atropine and scopolamine. The active agents in belladonna, atropine, hyoscine (scopolamine), and hyoscyamine, have anticholinergic properties. Scopolamine and atropine have similar effects on the peripheral nervous system. These plants contain deliriants, such as atropine and scopolamine, that cause hallucinations. In addition, scopolamine and low dose atropine can markedly increase HRV. The main psychoactive ingredients are the alkaloids scopolamine, and to a lesser extent, hyoscyamine. These include atropine, cyclopentolate, homatropine, scopolamine and tropicamide. Some of the chemicals tested on human subjects included mescaline and the anticholinergic drug scopolamine. Scopolamine can cause psychotropic effects when absorbed transdermally. Compare for example ipratropium, mirisetron, technepine, levomepate or scopolamine & atropine. It is a quaternary ammonium compound and a semisynthetic derivative of hyoscine hydrobromide (scopolamine). Scopolamine, which acts mainly on muscarinic receptors in the brain, can cause delirium and amnesia.