Kinetic analysis of neuromuscular blockade. II. Train-of-four fade induced by d-tubocurarine and alpha-bungarotoxin.
The degree of train-of-four (TOF) fade, i.e., the reduction of the fourth to the first twitch height in a train, induced by d-tubocurarine (d-TC) and alpha-bungarotoxin (alpha-BX) was investigated. The fade induced by d-TC was pronounced in comparison with that by alpha-BX, and the difference was analyzed using a kinetic model. Based on the assumptions: (1) Acetylcholine (ACh) binds to the nicotinic receptor and evokes twitch response. (2) The amount of released ACh is dependent on stimulus interval. (3) d-TC interacts competitively with the receptor. (4) alpha-BX interacts irreversibly with the receptor. It was suggested that the fade by d-TC and alpha-BX can be explained by the difference of the receptor occupancy by ACh which was caused by different interaction mechanisms of the two muscle relaxants with receptors.
Tajima
T
T
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Kato
Y
Y
Hatanaka
T
T
Aiba
T
T
Katayama
K
K
Koizumi
T
T
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D002038:Bungarotoxins / Q000493:pharmacokinetics / Q000494:pharmacology*; D004558:Electric Stimulation; D004594:Electrophysiology; D008297:Male; D008954:Models, Biological; D009466:Neuromuscular Blocking Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000187:drug effects; D014403:Tubocurarine / Q000493:pharmacokinetics / Q000494:pharmacology*
D002038:Bungarotoxins; D009466:Neuromuscular Blocking Agents; D011978:Receptors, Nicotinic; D000109:Acetylcholine; D014403:Tubocurarine