Expression of nicotinic acetylcholine receptor subunits alpha 4, alpha 7 and beta 2 in human internal mammary arteries of non-smokers and smokers

Nicotinic acetylcholine receptors (nAChR) are widely expressed in non-neuronal tissue, but data about their expression in vascular tissue are rare. To study the expression of nAChR α4, α7 and β2 in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in human arteries of smokers and non-smokers, arteriae thoracicae internae dissected for coronary artery bypass grafting were analysed immunhistochemically and by polymerase chain reaction (PCR). ECs of the tunica intima and the vasa vasorum as well as the VSMCs of the tunica media showed clear staining for nAChR α4, α7 and β2, without significant differences between non-smokers and smokers in all vascular layers. Further verification of nAChR α4, α7 and β2 expression of whole-tissue homogenates using PCR analysis showed no differences in the subtype expression between non-smokers and smokers. This provides an important basis for further investigations using positron electron tomography (PET) tracers for imaging of nAChRs in vascular health and disease.