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Aim: To study the effect of physostigmine and atropine on ciliary movement in frog buccal
Principle: Cilia in the buccal cavity and in the oesophagus helps in the movement of food particles. Similarly, the importance of mucociliary function has been established in the respiratory tract and of pulmonary diseases such as chronic bronchitis, asthma and cystic fibrosis. The integrity of mucociliary function is very important in these airway diseases. Cilia exhibit a great degree of autonomy in that they are capable of functioning in the absence of nervous innervations. It has also been demonstrated that the Ach present in the mucous membrane of the trachea and buccal cavity helps in the ciliary movement. Ach serves as a local hormone and the presence of choline acetylase support the fact that Ach is locally synthesised in the mucous membranes.
Drugs: Physostigmine stock solution (1µg/ml), Atropine stock solution (1µg/ml)
Physiological solution: Normal saline
- Decapitate the frog and pin the frog to the frog board on its back.
- Pin the lower jaw to the abdomen cutting sufficiently the buccal cavity and exposing the oesophagus wet by irrigating it with normal saline.
- To assess the distance travelled by the particles, fix two points. One starts from the lower jaw to the other beginning of the oesophagus. Keep this distance constant to measure the time taken by the particle to move from a fixed point in the lower jaw to the beginning of the oesophagus.
- Place a poppy seed or a small piece of cork at the premarked spot in the jaw. Turn on the stop watch and note the time taken by the object to reach the beginning of the oesophagus repeat this several times.
- Put a few drops of physostigmine on the buccal cavity and after 10 min repeat step 4 note the tome.
- Wash the buccal with normal saline. Put a few drops o atropine on the buccal cavity. After 10 min repeat step 4. Note the time.
- Find out the differences in the time taken by the object to move between the premarked distance in the buccal cavity in presence of saline, physostigmine and atropine.
Inference: Physostigmine reduces and atropine enhances the time taken by the object to move
from the pre-marked point in the lower jaw to reach the oesophagus, respectively.