hemicholinium-3

{{Short description|Chemical compound}}

{{Drugbox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 400103507

| IUPAC_name = (2S,2S)-2,2'-biphenyl-4,4'-diylbis(2-hydroxy-4,4-dimethylmorpholin-4-ium)

| image = Hemicholinium-3.svg

| alt = Skeletal formula

| width = 260

| image2 = Hemicholinium-3 cation spacefill.png

| alt2 = Space-filling model of the hemicholinium-3 cation

| tradename =

| legal_status =

| routes_of_administration =

| bioavailability =

| metabolism =

| elimination_half-life =

| excretion =

| IUPHAR_ligand = 4493

| CAS_number_Ref = {{cascite|correct|??}}

| CAS_number = 312-45-8

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 65NY3I7ZD0

| ATC_prefix = None

| ATC_suffix =

| PubChem = 9399

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 9029

| ChEMBL_Ref = {{ebicite|changed|EBI}}

| ChEMBL = 268697

| C=24 | H=34 | N=2 | O=4 |charge=2+

| smiles = [Br-].[Br-].OC1(OCC[N+](C)(C)C1)c2ccc(cc2)c3ccc(cc3)C4(O)OCC[N+](C)(C)C4

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C24H34N2O4.2BrH/c1-25(2)13-15-29-23(27,17-25)21-9-5-19(6-10-21)20-7-11-22(12-8-20)24(28)18-26(3,4)14-16-30-24;;/h5-12,27-28H,13-18H2,1-4H3;2*1H/q+2;;/p-2

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = OPYKHUMNFAMIBL-UHFFFAOYSA-L

| synonyms = 2-[4-[4-(2-hydroxy-4,4-dimethylmorpholin-4-ium-2-yl)phenyl]phenyl]-4,4-dimethylmorpholin-4-ium-2-ol

}}

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.{{cite book | first= Neil R. | last= Carlson | name-list-style = vanc | year= 2007 | title= Physiology of Behavior | edition=9th | location= Boston | publisher=Pearson Education, Inc. | isbn= 978-0-205-46724-2 | page= 117}}

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.