Brichant J F, Warner D O, Gunst S J, Rehder K
Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota 55905.
Am J Physiol. 1990 Jun;258(6 Pt 1):L349-54. doi: 10.1152/ajplung.1990.258.6.L349.
Prejunctional and postjunctional muscarinic receptor subtypes were characterized in canine trachealis muscle strips. In vitro contractile responses of muscle strips to acetylcholine or electric field stimulation were determined in the absence and the presence of gallamine, pirenzepine, and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP). Gallamine had no effect on the contractile response to acetylcholine but enhanced the contractile response to electric field stimulation. Pirenzepine and 4-DAMP reduced the contractile response to acetylcholine and electric field stimulation. The pA2 value for pirenzepine vs. acetylcholine [7.18 +/- 0.59 (SD)] was consistent with the affinity of pirenzepine for M2 or M3-receptors; whereas the pA2 value for 4-DAMP vs. acetylcholine (8.92 +/- 0.42) and the extremely low affinity of gallamine indicated postjunctional muscarinic receptors of the M3 subtype. The enhancement of the contractile response to electric field stimulation by gallamine suggested the presence of M2-prejunctional receptors.
在犬气管肌条中对接头前和接头后毒蕈碱受体亚型进行了表征。在有无加拉明、哌仑西平以及4-二苯基乙酰氧基-N-甲基哌啶甲碘化物（4-DAMP）的情况下，测定了肌条对乙酰胆碱或电场刺激的体外收缩反应。加拉明对乙酰胆碱的收缩反应无影响，但增强了对电场刺激的收缩反应。哌仑西平和4-DAMP降低了对乙酰胆碱和电场刺激的收缩反应。哌仑西平相对于乙酰胆碱的pA2值[7.18±0.59（标准差）]与哌仑西平对M2或M3受体的亲和力一致；而4-DAMP相对于乙酰胆碱的pA2值（8.92±0.42）以及加拉明极低的亲和力表明存在M3亚型的接头后毒蕈碱受体。加拉明对电场刺激收缩反应的增强提示存在M2接头前受体。
