title: Organic cation transporter 2 (SLC22A2), a low-affinity and high-capacity choline transporter, is preferentially enriched on synaptic vesicles in cholinergic neurons.
abstract: Organic cation transporters (OCTs) are expressed mainly in the kidney and liver. OCTs transport intrinsic organic cations, including monoamine, dopamine, serotonine and choline, across the plasma membrane. Here, we demonstrate that OCT2 (SLC22A2) is expressed in cholinergic neurons, motoneurons in the anterior horn of the spinal cord, and is implicated in acetylcholine (Ach) recycling in presynaptic terminals. Application of rabbit anti-peptide antibody revealed that OCT2 was expressed in the anterior horn of the spinal cord. Double immunostaining of muscle sections with anti-OCT2 and alpha-bungarotoxin (BTX) revealed that OCT2 was localized in the neuromuscular junctions (NMJs). Immunoelectron microscopy revealed that OCT2 was localized both in synaptic vesicles (SVs) in presynaptic terminals around the motoneurons (C-terminals) and in SVs in nerve terminals in NMJs. The similarity in the distribution of OCT2 in cholinergic neurons and that of vesicular acetyl choline transporter (VAchT), and the fact that OCT2 can transport choline suggest that OCT2 could work as a low-affinity and high-capacity choline transporter at presynaptic terminals in cholinergic neurons in a firing-dependent manner.
authors: Department of Health Science, Ishikawa Prefectural Nursing University, 1-1 Gakuendai, Kahoku, Ishikawa 929-1210, Japan; Department of Anatomy and Neurobiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan. Electronic address: tnakata1@mail.goo.ne.jp.
authors: T
authors: T
authors: Nakata
authors: T
authors: T
authors: Matsui
authors: K
authors: K
authors: Kobayashi
authors: Y
authors: Y
authors: Kobayashi
authors: N
authors: N
authors: Anzai
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D059329:Cholinergic Neurons / Q000378:metabolism*; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D009046:Motor Neurons / Q000378:metabolism; D027701:Organic Cation Transport Proteins / Q000096:biosynthesis*; D000075102:Organic Cation Transporter 2; D051381:Rats; D013572:Synaptic Vesicles / Q000378:metabolism*
chemical_list: D027701:Organic Cation Transport Proteins; D000075102:Organic Cation Transporter 2; C100590:Slc22a2 protein, rat; D000109:Acetylcholine
keywords: 3,3′-diaminobenzidine; Ach; AchR; BTX; CA; CC; CNS; ChAT; Co; DAB; DMEM; DPX; Dulbecco’s modified Eagle’s medium; ER; FCS; HC-3; HRP; Is; KLH; MBS; NGS; NMJs; OCT2; OCTs; Os; PB; PBS; PC; SLC22A2; SVs; TM; VAchT; acetyl choline receptors; acetylcholine; alpha-bungarotoxin; central autonomic cells; central canal; central nervous system; choline acetyltransferase; cholinergic neuron; cortex; dibutyl phthalate xylene; endoplasmic reticulum; fetal calf serum; hemicholinium; horseradish peroxidase; inner stripe of the outer medulla; keyhole limpet hemocyanin; m-maleimidobenzoyl-N-hydroxysuccinimide ester; neuromuscular junctions; normal goat serum; organic cation transporter; organic cation transporters; outer stripe of the outer medulla; partition cells; phosphate buffer; phosphate-buffered saline; synaptic vesicle; synaptic vesicles; transmembrane; vesicular acetyl choline transporter