Comparison of the effects of carbamyl-β-methylcholine chloride administered by intravenous, intramuscular and intra-acupuncture point injections

ObjectiveTo compare the effects of carbamyl-β -methylcholine chloride (CMCC) administered by intra-acupuncture point injection (IAI), intramuscular injection (IMI), and intravenous injection (IVI), and to analyze the mechanisms.MethodsIn the IAI group, CMCC was injected into the Zusanli acupoint (ST 36) immediately after 30-min stimulation by electro-acupuncture (EA) at the acupoints, and into the femoral vein and skeletal muscle in IVI and IMI groups, respectively. Intragastric pressure was detected. The plasma concentration of CMCC was measured at various times.ResultsThe gastric effect of CMCC in the IVI group was enhanced and attenuated more rapidly than in the other groups. In the IAI group, this effect was significantly stronger than that in the IMI group at 2 min and 15 min, but not significantly different between the two groups at 5 min and 30 min. Plasma concentration of CMCC in the IAI group was similar to that in the IVI group at 2 min, but higher than that in the IMI group. The concentration in the IAI group was higher than that in the IV group and similar to that in the IMI group at 5, 15 and 30 min, indicating rapid increase and slower reduction of the plasma concentration of the drug in the IAI group. There was a positive correlation between the plasma concentration of CMCC and intragastric pressure in all groups.ConclusionThe effect of IAI with CMCC was stronger than that of IMI and longer-lasting than that of IVI, which correlated with the blood concentration of CMCC.