1.
Effect Of Eserine On The Action Of Acetyl
Choline On Frog Rectus Muscle

2.
Aim
 To determine the action of eserine on the action of Acetyl Choline on
the frog rectus

3.
Apparatus
 Recording Drum or Kymograph
 Stand with lever
 Bent glass tube
 Frog dissection instruments

4.
Procedure
 A pitched frog dissected and rectus abdominis exposed
 Lower end is fastened to bent glass tube
 Muscle immersed in beaker containing ringer
 Two normal contractions are recorded with interval of 3 min
 Eserine is added to medium and amplitude of contraction is observed

5.
Observation
 Observations are recorded on recording drum and interpreted

6.
Inference
 Eserine potentiates the effect of Acetylcholine on muscle
 It inhibits both true and pseudo cholinesterase
 Causes accumulation of choline at motor end plate and hence
increased amplitude of contraction

7.
Effect Of d-Tubocurarine On The Action Of
Acetyl Choline On Frog Rectus Muscle

8.
Aim
 To know the effects of d-Tubocurarine on Acetylcholine contractions
of frog rectus muscle

9.
Apparatus
 Kymograph or Recording drum
 Frog dissection instruments
 Oxygen tube
 Aerator
 Simple lever

10.
Solutions
 Frog ringer solution ( Nacl : 9gm, Kcl : 0.42 gm, Cacl2 : 0.24gm,
NaHCo3 :0.5 gm, Distilled Water : 1.4 lit
 Acetylcholine 1microgram/ml
 d-Tubocurarine 2 microgram/ml

11.
Dissection
 A pitched frog is laid on a plate.
 Skin of the abdominal wall is cut and open.
 Identify the horizontal ladder like fibrous bands of rectus abdominis
muscle.
 Separate both muscles from the abdominal wall.
 Pass threads underneath the muscle.
 Tie the upper ends and lower ends.

12.
 Swipe off the upper end with a piece of xiphisternum and lower end with pubic
attachment.
 The muscle with threads is kept in a beaker with lower end is tied to the
oxygen tube and upper end to the simple lever.
 It has a counter weight or load of 1.4gm using plasticine.
 A beaker of ringer solution is kept under the oxygen tube and oxygen is
allowed to pass.
 Leave the preparation for half an hour.
 Put sufficient load so that the contractions will be able to raise the lever
Dissection

13.
Procedure
 The drum is started and is allowed to rotate for 15 sec
 After 15 sec, the ringer solution is changed with Acetylcholine solution.
 After 90 sec, it is replaced with frog ringer solution.
 The muscle that contracts during Ach exposure, slowly relaxes and comes to
original position
 Repeat the process until you get equal contractions with Ach.
 Now immerse the muscle in d-Tc solution for 30 sec
 Replace with Ach and repeat contractions
 If 10 micrograms of d-Tc is given, complete depression of Ach contraction is seen

14.
Observation
 Stimulatory action of Ach on rectus abdominis muscle
 Blocking action of curare or d-Tc on Ach induced contractions of
rectus muscle