Nicotine also counteracts anticholinergics by activating nicotinic acetylcholine receptors. Nicotinic acetylcholine receptors are activated by the neurotransmitter acetylcholine. BZ is an antagonist of muscarinic acetylcholine receptors. Its pharmacological effects are due to binding to muscarinic acetylcholine receptors. Choline is a precursor for the neurotransmitter acetylcholine. Beta-neurotoxins keep nerve endings from liberating the neurotransmitter acetylcholine. These chemical neurotransmitters include dopamine, serotonin, GABA, glutamate, and acetylcholine. This results in hyperpolarization of cholinergic neurons, which inhibits the release of acetylcholine. The vagus (parasympathetic) nerves that innervate the heart release acetylcholine (ACh) as their primary neurotransmitter. Benzatropine is an anticholinergic which works by blocking the activity of the muscarinic acetylcholine receptor. First, the toxin binds specifically to nerves which use the neurotransmitter acetylcholine. Botulism toxin blocks the exocytosis of presynaptic vesicles containing acetylcholine (ACh). Spinosoid binding leads to disruption of acetylcholine neurotransmission. Levels of the neurotransmitter acetylcholine (ACh) are reduced. Strychnine is a neurotoxin which acts as an antagonist of glycine and acetylcholine receptors.