Morphological correlates of the differential responses of muscles to vecuronium.

摘要: We have noted previously that duration of vecuronium block correlated with fibre size in six muscle groups the goat. Electrophysiological considerations suggest important factor should be number acetylcholine receptors (AChR) relative to size. However, this hypothesis could not verified goat because AChR was relatively constant different muscles despite differences Therefore, study, we investigated relationship between sensitivity vecuronium, as reflected by ED50 and block, cat per unit cross-sectional area (CSA). The action (time 50% recovery first twitch after a dose 15 micrograms kg-1) tibialis cranialis, soleus, rectus abdominis, masseter, diaphragm thyroarytenoideus were determined during train-of-four stimulation EMG recording seven cats anaesthetized pentobarbital. CSA fibres junctional these measured histological methods 125I-alpha-bungarotoxin binding assay, respectively, calculated. association response (ED50 block) or then tested regression analyses. Duration varied (mean 8.9 (SEM 2.6) 20.3 (3.1) min; P = 0.0001) but did (7.5 (1.5) 15.6 (2.5) kg-1; 0.185). Fibre also (P 0.0001). TI prolonged low (r2 0.30; 0.0002) increased 0.240; 0.0016). These results is morphological predictor differential sensitivities neuromuscular blocking agents.