R. Ochillo, C. Tsai
Research communications in chemical pathology and pharmacology
The responsiveness of the cholinergic receptor (ChR) of the isolated ileum of mouse and rat was characterized by determining the ED50 of acetylcholine (ACh) and pA2 of mepenzolate (MPZ) in tissues from animals of different ages. The ages (in months) of mice were 3, 6 and 18 and; 3, 6, 12 and 24 for rats respectively. The responsiveness of ChR in mice and rats decreased with age. There was no difference in the pA2 between the preparations derived from mice and rats nor was it affected by age. The results of this investigation suggest that (1) changes in the peripheral ChR with age may have potential in the understanding of central aging process and (2) the use of age rather than the weight of animal may provide reproducible data in studies using isolated preparations.