|Chemical and physical data|
|Molar mass||414.538 g/mol g·mol−1|
|3D model (JSmol)|
|(what is this?)|
Hemicholinium-3 (HC3), also known as hemicholine, is a drug which blocks the reuptake of choline by the high-affinity choline transporter (ChT; encoded in humans by the gene SLC5A7) at the presynapse. The reuptake of choline is the rate-limiting step in the synthesis of acetylcholine; hence, hemicholinium-3 decreases the synthesis of acetylcholine. It is therefore classified as an indirect acetylcholine antagonist.
Acetylcholine is synthesized from choline and a donated acetyl group from acetyl-CoA, by the action of choline acetyltransferase (ChAT). Thus, decreasing the amount of choline available to a neuron will decrease the amount of acetylcholine produced. Neurons affected by hemicholinium-3 must rely on the transport of choline from the soma (cell body), rather than relying on reuptake of choline from the synaptic cleft.
Hemicholinium-3 is highly toxic because it interferes with cholinergic neurotransmission. The LD50 of hemicholinium-3 for mice is about 35 μg.
- Carlson, Neil R. (2007). Physiology of Behavior (9th ed.). Boston: Pearson Education, Inc. p. 117. ISBN 0-205-46724-5.
- Freeman, JJ; Kosh, JW; Parrish, JS (October 1982). "Peripheral toxicity of hemicholinium-3 in mice". British Journal of Pharmacology. 77 (2): 239–44. doi:10.1111/j.1476-5381.1982.tb09291.x. PMC 2044599. PMID 7139185.