Aim: Effect of drugs on ciliary motility of frog oesophagus
Reference:
Thomas N. Thompson & Curtis D. Klaassen. The Effects of Hepatic Microsomal Enzyme Inducers on the Pharmacokinetics of Ouabain after Portal and Systemic Administration to Rats. Journal of Pharmacy and Pharmacology, Volume 47, Issue 12A, December 1995, Pages 1041–1047.
Introduction:
Ciliary motility plays a vital role in the movement of mucus and foreign particles across epithelial linings in various body systems, including the respiratory and digestive tracts. Pharmacological agents can influence ciliary function either by stimulating or inhibiting the activity of ciliated epithelial cells. This experiment aims to explore the impact of specific drugs—acetylcholine, atropine, adrenaline, and pilocarpine—on the ciliary activity of frog oesophagus tissue under a dissecting microscope.
Materials and Equipment:
Animals: Healthy adult frogs
Drugs and Chemicals: Acetylcholine, Atropine, Adrenaline, Pilocarpine, Saline solution (control)
Equipment: Dissecting microscope, Dissecting tools (scissors, forceps), Petri dishes, Physiological saline, Glass slides and coverslips, Dropper or micropipette, Stopwatch or timer
Method:
1. Preparation of Frog Oesophagus:
Frogs were sacrificed humanely following institutional ethical guidelines. The oesophagus was carefully dissected and immediately transferred to a Petri dish containing physiological saline to preserve tissue viability.
2. Preparation of Tissue Samples:
Small strips (~1 cm) of the oesophagus were cut and mounted on clean glass slides using a few drops of saline to maintain hydration. Coverslips were gently placed to avoid crushing the tissue.
3. Baseline Observation:
The slides were placed under a dissecting microscope, and the normal (baseline) ciliary activity was observed. The frequency and pattern of ciliary beats were noted to serve as a control reference.
4. Drug Application:
Each test drug was applied separately by replacing the saline with a few drops of the specific drug solution:
Acetylcholine (Ach): A cholinergic agonist expected to increase ciliary motility.
Atropine: A cholinergic antagonist likely to inhibit Ach-mediated effects.
Adrenaline: A sympathomimetic agent, possibly producing variable effects on cilia.
Pilocarpine: Another cholinergic agonist, expected to stimulate ciliary movement.
For each drug, fresh tissue samples were used to avoid cross-contamination or desensitization.
5. Observation and Data Recording:
After drug application, the time to onset of action and duration of the effect were measured using a stopwatch. Changes in ciliary motility were observed and compared to baseline values.
Observations (Sample Table):
| Drug | Effect on Ciliary Motility | Time to Onset (s) | Duration of Effect (min) |
| Control (Saline) | No change | – | – |
| Acetylcholine | Increased motility | 10 | 15 |
| Atropine | Decreased motility/Inhibition | 20 | 25 |
| Adrenaline | Variable (increase/decrease) | 15 | 20 |
| Pilocarpine | Increased motility | 10 | 15 |
Note: These values are indicative. Actual readings may vary depending on lab conditions.
Results and Interpretation:
Acetylcholine: Caused a significant increase in ciliary movement, confirming its role in stimulating muscarinic receptors.
Atropine: Reduced ciliary motility by blocking the cholinergic action of acetylcholine, acting as an antagonist.
Adrenaline: Produced mixed effects—some preparations showed stimulation, while others showed inhibition—suggesting interaction with adrenergic receptors.
Pilocarpine: Similar to acetylcholine, increased ciliary activity due to its agonistic action on cholinergic receptors.
Precautions:
- Animals must be handled humanely in accordance with ethical and IAEC guidelines.
- All drug solutions should be freshly prepared and used under aseptic conditions.
- Maintain a consistent temperature and light environment during observation.
- Avoid contamination between different drug applications.