Presynaptic cholinergic nerve terminal surface receptors

Presynaptic cholinergic nerve terminal surface receptors are a heterogeneous group of membrane-bound proteins and molecules that regulate the release of acetylcholine (ACh) into the synaptic cleft. This group primarily includes muscarinic acetylcholine receptors (specifically the M2 and M4 subtypes), which act as inhibitory autoreceptors to provide negative feedback on ACh release (Billard, 2012) [1]. Additionally, these terminals express nicotinic acetylcholine receptors (nAChRs) and various heteroreceptors that modulate neurotransmission. From a pharmacological perspective, these surface receptors are the critical initial binding sites for Botulinum neurotoxins (BoNTs); for instance, BoNT/A binds to Synaptic Vesicle Protein 2 (SV2), while BoNT/B binds to synaptotagmin II (Rummel, 2015) [2]. These interactions are essential for the internalisation of toxins that subsequently cleave SNARE proteins, leading to prolonged inhibition of muscle contraction. Consequently, these receptors are therapeutic targets for treating focal dystonias, spasticity, and chronic migraine, though their modulation requires precise dosing to avoid systemic paralysis or autonomic side effects (Pirazzini et al., 2017) [3]. The study of these receptors is also vital for understanding neurodegenerative conditions like Alzheimer's disease, where presynaptic cholinergic dysfunction is a hallmark. Overall, they represent a key interface for both therapeutic intervention and toxicological impact in the peripheral and central nervous systems.

Other names

Presynaptic cholinergic receptorsCholinergic autoreceptorsBotulinum toxin binding sitesPresynaptic muscarinic receptorsPresynaptic nicotinic receptors

Drugs targeting these receptors primarily act by modulating the release of acetylcholine. Botulinum neurotoxins bind to surface components like Synaptic Vesicle Protein 2 (SV2) or synaptotagmin to enter the neuron and cleave SNARE proteins, thereby blocking exocytosis. Muscarinic agonists and antagonists interact with M2/M4 autoreceptors to inhibit or enhance acetylcholine release via G-protein signaling pathways.