The difference in number and distribution of acetylcholine receptor in post-synaptic membrane of neuromuscular junction between young adult and elderly rats

Abstract

Objective To examine the difference in the number and distribution of acetylcholine receptor(AChR)in post-synaptic membrane of neuromuscular junction between young adult and elderly rats.Methods Ten male Wistar rats were divided into 2 age groups(n = 5 each): group Ⅰ 4-6 months old and group Ⅱ 24-28 months old.The expression of nicotinic AChR in gastrocnemius muscle was detected by quantitative real-time PCR(qRT-PCR).Primers were designed according to the mRNA subsequence of e-subunit of AChR.The post-synaptic AChR in gastrocnemius muscle was labeled with tetramethyl-rhodamine-α-bungarotoxin.The distribution of post-synaptic AChR was investigated by confocal microscopy.The area,length and width of AChR region were calculated by computer.Results There was significant difference in AChR expression between the 2 groups.Furthermore a significant difference in distribution structure of AChR was found by confocal microscopy.There was no significant difference in the area,length and width of post-synaptic receptor region between the 2 groups.Conclusion Elderly rats have a low level of AChR expression but the area of neuro-muscular junction does not change significantly with age. Key words: Receptors,cholinergic ; Neuromuscular junction; Syuaptic membranes; Aged