Appearance of tolerance in the increase of contractile muscle tension by ambenonium in rats.
The relationship between the concentration of ambenonium (AMB), a selective and reversible acetylcholinesterase (AChE) inhibitor, in plasma and the potentiation of contractile muscle tension was investigated using a sciatic nerve-muscle preparation of rat. The developed isometric contraction was enhanced dose-dependently after i.v. administration of low doses (5-20 nmol/kg) of AMB, but the contraction was weakened when AMB was administered at high doses (100-1000 nmol/kg), and the concentration-effect relationship was bell-shaped. The muscle contraction profile after 50 nmol/kg administration without previous administration, with 20 nmol/kg and with 50 nmol/kg administered previously were quite different from each other. These findings suggest that the potentiation of contractile muscle tension by AMB may be acutely tolerated and the concentration-effect relationship may change time-dependently.
Yamamoto
K
K
Department of Pharmacy, University of Tokyo Hospital, Faculty of Medicine, Japan.
Sawada
Y
Y
Iga
T
T
D000549:Ambenonium Chloride / Q000097:blood / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
D000549:Ambenonium Chloride