Identification of vesicular acetylcholine transporter mRNA in selected brain and peripheral tissues by RT-PCR

The vesicular acetylcholine transporter (VAChT) is a proton antiporter responsible for the accumulation of acetylcholine (ACh) in cholinergic neuron secretory vesicles. The mRNA encoding the VAChT was previously shown by in situ hybridization to exhibit a brain distribution similar to that of other cholinergic neuronal markers, though none were detected in some regions for which the existence of ACh soma has been questioned. In the present study, reverse-transcription polymerase chain reaction (RT-PCR) was employed to amplify a 440 bp fragment of rat VAChT mRNA in several brain and ganglionic regions. VAChT mRNA was detected in each brain region examined, including the striatum, frontal cortex, hypothalamus, cerebellar cortex, and medulla. Further, this mRNA species was detected in the hippocampus, a region which had previously failed to hybridize in situ probes for the VAChT and other cholinergic mRNAs. VAChT mRNA was also detected in tissues associated with otic ganglion, celiac and superior mesenteric ganglion, and cardiac ganglion. These data indicate that VAGhT mRNA is a marker for cell bodies exhibiting the cholinergic phenotype and that such cells are localized in many regions in which their presence has been difficult to confirm.