The interaction of neuromuscular relaxants with rabbit lung muscarinic receptors.
The interaction of muscle relaxants with airway muscarinic receptors of rabbit lung was investigated in vitro by the [3H]QNB binding technique. Pancuronium, vecuronium, alcuronium and succinyl choline chloride (SCC) inhibited the binding of [3H]QNB to rabbit lung muscarinic receptors in a dose-dependent manner. The values of IC50 (the concentration giving 50% inhibition) of pancuronium, vecuronium, alcuronium and SCC were 1.54 x 10(-5), 2.52 x 10(-5), 8.40 x 10(-5), and 4.00 x 10(-3) mol/l respectively. As the values of Kd increased with minimal change in the value of Bmax, while not influencing the number of receptors, these muscle relaxants had an inhibitory action on the affinity of muscarinic receptors to [3H]QNB in the order: pancuronium greater than or equal to vecuronium greater than alcuronium greater than SCC. Applying IC50 values to human conditions, clinical doses of these muscarinic relaxants are unlikely to exhibit any significant vagolytic action in lung tissue.
Sugai
Y
Y
Department of Anesthesiology, Ohmihachiman City Hospital, Shiga, Japan.
Sugai
K
K
Mishima
M
M
Okuda
C
C
Miyazaki
M
M
D000443:Alcuronium / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D046508:Culture Techniques; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D010197:Pancuronium / Q000494:pharmacology*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D011817:Rabbits; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000378:metabolism; D013390:Succinylcholine / Q000494:pharmacology; D014117:Toxiferine / Q000031:analogs & derivatives*; D014673:Vecuronium Bromide / Q000494:pharmacology*
D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; D014673:Vecuronium Bromide; D014117:Toxiferine; D013390:Succinylcholine; D010197:Pancuronium; D000443:Alcuronium