ABSTRACT
The most important use of neuromuscular blockers is as adjuvant to general anaesthesia where adequate muscle relaxation can be achieved at lighter plane. They also reduce reflex muscle contraction in the region undergoing surgery and assist maintenance of controlled ventilation during anaesthesia. They are particularly helpful in abdominal and thoracic surgery, intubations and endoscopies, orthopedic manipulation, etc. Thus, the risk of respiratory and cardiovascular depression is minimized, and post anesthetic recovery is shortened. The potency ratio of two commonly used neuromuscular agents depolarizing succinylcholine and non depolarizing pancuronium. Double pith a frog and fasten it to a frog board with ventral side up. The sternum was cut through just above the xiphisternum at its base and a pair of muscle attached to it were dissected out and transferred to a dish containing frog Ringer solution at room temperature. All the drug containing solutions were freshly prepared before the experiments Succinyl choline, Pancuronium (1,10,100mg/ml and 1mg/dl) respectively Acetyl choline (10,100mg/ml and 1mg/dl). Acetylcholine solution in various strength were prepared starting from 0.1% to 0.0001%.NMJ blocker Pancuronium was added to the biophase in addition to selected dose (128mg or 256mg) and the contraction of muscle till the 70-80% of inhibition is produced and the difference from sub maximal contractions. The median ED50 was interpolated from the figure taking 50%of inhibition from Height of contraction in mm. The ‘t’ test was performed to compare the ED50 value were interpolated from the regression line to find out the ED50 of the drug. The median doses (ED50) of both of them were calculated graphically and compared. The mean ED50 value of succinylcholine was found to be 1.59 ± 0.08μg (95% confidential limit was from 1.53 to 1.66μg). The ED50 of pancuronium was found to be 0.52 ± 0.10μg with 95% confidence limit being from 0.44 to 0.60μg. The ED50 value of the two drugs was very significantly different (P < 0.001). The potency ratio of pancuronium to succinylcholine was 0.32.