laboratory experiments in pharmacology

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Commonly used instruments in experimental pharmacology

BP408P Pharmacology I Practical / S Y B Pharmacy Notes

In spite of tremendous development in electronic devices and recording systems are followed in institutions and research laboratories. Some common instruments are used in experimental pharmacology

Organ bath:

The tissue bath used to put the animal tissue for studying the drug actions is called the student organ bath. This was first designed by Rudolph Magnus in 1904. The organ bath essentially consists of

• An outer jacket is made of up of steel or glass or Perspex.
• The inner organ or tissue bath is made up of glass with a capacity varying from 10 -50 ml
• Thermostatically controlled heating rod
• Stirrer to keep the water in the outer jacket at a uniform temperature
• Oxygen or delivery glass tube which also serves as tissue holder
• Glass coil, one end of which is connected having the physiological salt solution.

The student organ bath having two units of inner tissue bath is called a double unit organ bath.

• Purpose: The student organ bath is primarily used to assess the effects of drugs on smooth muscle tissue. Smooth muscles are found in various organs such as the intestine, blood vessels, uterus, and bronchioles. By isolating and studying these tissues, researchers can understand the mechanisms of drug actions and their potential therapeutic applications.
• Construction: The organ bath typically consists of a glass or plastic chamber filled with physiological solution, maintained at a constant temperature (usually 37°C) using a temperature-controlled water bath. The tissue sample is mounted between two hooks or wire loops attached to a force transducer, which measures the changes in tension caused by the muscle contractions or relaxations.
• Experimental Setup: The tissue is carefully dissected, cleaned, and then mounted in the organ bath. One end of the tissue is attached to a fixed hook, while the other end is connected to an adjustable hook connected to the force transducer. The force transducer converts mechanical tension into electrical signals that can be recorded and analyzed.
• Recording and Analysis: The force transducer is connected to a data acquisition system or a recording device, such as a physiograph or a computer-based system, to measure and record the changes in tension produced by the tissue. This allows researchers to analyze and quantify the effects of different drugs or experimental interventions on the tissue’s contractile or relaxant responses.
• Drug Administration: Drugs or pharmacological agents can be administered directly into the organ bath by adding them to the physiological solution surrounding the tissue. The response of the tissue to the drug is then recorded, allowing researchers to study the drug’s effects on muscle contraction, relaxation, or other relevant parameters.
• Applications: The student organ bath is used to investigate various pharmacological properties, including drug-receptor interactions, dose-response relationships, mechanisms of action, and comparative studies between different compounds. It is particularly valuable in studying the effects of drugs on smooth muscle tissue, such as evaluating the relaxant effects of bronchodilators on airway smooth muscle or investigating the contractile responses of the uterus to oxytocic agents.

The student organ bath provides a controlled and reproducible experimental platform for pharmacological research and plays a crucial role in understanding the effects of drugs on isolated tissues. It helps in elucidating the mechanisms of action, identifying potential therapeutic applications, and contributing to the overall knowledge of pharmacology.

Rota rod apparatus:

The rota rod apparatus is a common piece of equipment used in pharmacology and neuroscience research to assess motor coordination and balance in laboratory animals, typically rodents. It consists of a rotating rod or cylinder on which animals are placed and their ability to remain on the rod as it rotates is measured. Here’s how the rota rod apparatus is used in pharmacology labs:

• Motor Coordination Assessment: The primary purpose of the rota rod apparatus is to evaluate motor coordination and balance in animals. It is used to assess the effects of drugs or experimental interventions on an animal’s ability to maintain its balance and coordination while the rod rotates at a constant speed or accelerates gradually.
• Experimental Design: Animals, often mice or rats, are placed individually on the rod, and the apparatus is set to rotate at a specific speed or acceleration rate. The time each animal stays on the rotating rod before falling off is measured. Typically, multiple trials are conducted to obtain reliable data, and the average time or latency to fall is calculated.
• Drug Effects: The rota rod apparatus is commonly used to assess the effects of drugs that may affect motor coordination and balance. Researchers administer the drug to the animals through various routes, such as oral gavage or injection, and then evaluate their performance on the rotating rod. This helps determine if the drug impairs or improves motor coordination and balance.
• Dose-Response Relationships: By administering different doses of a drug, researchers can establish dose-response relationships. This allows them to determine the minimum effective dose required to produce an effect or the maximum tolerated dose before severe impairment occurs. The rota rod apparatus can help determine the optimal dosage for therapeutic interventions or identify potential adverse effects.
• Disease Models: The rota rod apparatus is also used to study motor impairments associated with neurological disorders or conditions. Animal models of diseases such as Parkinson’s disease or cerebellar ataxia can be tested on the rota rod to assess the severity of motor deficits and evaluate the efficacy of potential treatments.
• Data Analysis: The data collected from the rota rod experiments are typically analyzed using statistical methods. Graphs are plotted to show the performance of animals over time or dose, and statistical tests such as ANOVA or t-tests are applied to compare groups and determine the significance of the observed effects.

For the study of the muscle relaxant property of diazepam in mice. The loss of muscle grab is an indicator of muscle relaxation. This effect can be studied in animals using an inclined plane or rotating rods.

Actophotometer:

An actophotometer is a device commonly used in pharmacology laboratories to measure the activity and behavior of laboratory animals, particularly rodents, in response to pharmacological interventions or other stimuli. It is designed to quantify and analyze various aspects of animal locomotor activity.

Here’s an overview of how an actophotometer works and its applications in pharmacology labs:

• Principle: An actophotometer typically consists of an enclosed chamber or an open-field arena equipped with infrared or visible light beams or sensors. The animal’s movement, detected by the sensors, is converted into electrical signals and recorded by a computer or data acquisition system.
• Measurement Parameters: Actophotometers can measure several parameters related to animal activity, including: a. Locomotor Activity: The device records the distance traveled by the animal over a specific period, providing quantitative data on overall motor activity. b. Exploration and Resting Behavior: By analyzing the animal’s movement patterns, researchers can assess exploration (such as time spent in the center versus periphery of the arena) and resting behavior. c. Stereotypic Behavior: The actophotometer can detect repetitive and stereotyped movements, which can indicate abnormal behavior in certain experimental conditions. d. Anxiety and Fear Response: Changes in animal behavior related to anxiety or fear can be measured using specific paradigms, such as the open-field test or elevated plus maze, in the actophotometer.
• Pharmacological Applications: Actophotometry is widely used in pharmacology research to evaluate the effects of drugs or experimental interventions on animal behavior and locomotor activity. It allows researchers to study the following: a. Drug Screening: Actophotometers are used to assess the effects of drugs on locomotor activity and explore potential therapeutic uses or side effects. They can help identify drugs that increase or decrease locomotor activity, or influence specific aspects of behavior. b. Toxicity and Side Effects: Actophotometry can aid in evaluating the toxicity of drugs by monitoring changes in animal activity patterns or detecting abnormal behaviors associated with adverse drug reactions. c. Central Nervous System Research: Actophotometers are instrumental in studying the effects of drugs on the central nervous system (CNS). They can assess the impact of pharmacological agents on parameters like motor coordination, exploratory behavior, and anxiety-related responses. d. Animal Models: Actophotometers assist in establishing animal models for conditions such as Parkinson’s disease, schizophrenia, depression , or anxiety disorders. By measuring changes in locomotor activity, researchers can assess the efficacy of potential treatments or the underlying mechanisms of these conditions.

It is used to study the CNS depressant property of chlorpromazine on the locomotor activity of mice. CNS depressant drugs like alcohol reduce motor activity the stimulants like caffeine and amphetamines increase the activity. The actophotometer operates on the photoelectric cell which is connected to a circuit with the counter.

Electro-convulsiometer

An electroconvulsiometer, also known as an electroconvulsive therapy (ECT) device, is a piece of equipment used in pharmacology and medical research to induce seizures in laboratory animals. Here are some key points about electroconvulsiometers and their use in pharmacology labs:

• Purpose: Electroconvulsiometers are primarily used to study the effects of convulsive seizures on the central nervous system and to evaluate the efficacy of potential anti-convulsant drugs. These devices are crucial for understanding the mechanisms of seizures and developing new treatments for epilepsy and other related conditions.
• Seizure Induction: Electroconvulsive seizures can be induced by passing electrical currents through the brain, typically using electrodes attached to the animal’s scalp or ears. The electroconvulsiometer delivers controlled electrical stimuli to the brain, resulting in a generalized seizure.
• Parameters: The electroconvulsiometer allows researchers to control various parameters of the induced seizures, such as the duration, intensity, frequency, and waveform of the electrical stimulus. These parameters can be adjusted to mimic different seizure types or to assess the effects of various interventions or drug treatments.
• Animal Models: Laboratory animals, such as rats or mice, are commonly used in pharmacology research involving electroconvulsive seizures. These models help researchers understand the underlying mechanisms of seizures, evaluate the effectiveness of potential therapies, and investigate the side effects or adverse events associated with convulsive treatments.
• Data Collection: Electroconvulsiometers are often equipped with sensors and recording devices to measure and record various physiological parameters during and after the induced seizures. These parameters may include electroencephalography (EEG) readings, heart rate , blood pressure, and other relevant data. The recorded information helps researchers assess the severity and duration of the seizures and analyze the effects of different interventions.
• Ethical Considerations: The use of electroconvulsiometers in animal research is subject to ethical guidelines and regulations to ensure the welfare and humane treatment of the animals involved. Researchers must obtain appropriate ethical approvals and follow strict protocols to minimize distress and discomfort during the experiments.
• Limitations: While electroconvulsive therapy has been a valuable tool in pharmacological research, it is important to acknowledge the limitations and differences between induced seizures in animal models and the clinical manifestations of seizures in humans. Animal models provide insights into seizure mechanisms and drug responses, but they may not fully replicate the complex nature of human epilepsy.

It is used to study the anticonvulsant activity of phenytoin against electro-convusiometer induced in rats. The electric shock is applied through the corneal electrodes; it produces 5 phases such as tonic flexion, tonic extensor, clonic convulsion, stupor, and recovery/death.

Pole climbing apparatus

A pole climbing apparatus is a commonly used tool in pharmacology labs to study the anxiolytic (anti-anxiety) activity of various compounds or drugs. Here’s how it works:

• Setup: The pole climbing apparatus typically consists of a vertical pole or rod with a height of several feet, which is fixed securely in a stable base. The pole may have a rough texture or grid-like surface to facilitate climbing. At the top of the pole, there is usually a platform or ledge where the animal can rest.
• Experimental Animals: Small laboratory animals, such as mice or rats, are used in these experiments. They are selected and divided into different groups for comparison, including a control group and groups receiving different doses of the test compound.
• Anxiety-Inducing Environment : The animals are placed in an anxiety-inducing environment, such as a brightly lit and open space, which naturally triggers anxiety-like behavior in rodents. This environment motivates the animals to climb the pole to seek safety and avoid the anxiety-inducing situation.
• Test Sessions: Each animal is subjected to a series of test sessions. In each session, the animal is placed at the base of the pole, and the time taken to climb to the top platform is recorded. The latency to climb the pole is an important measure of anxiety-like behavior, with longer latencies indicating higher anxiety levels.
• Drug Administration: Depending on the experimental design, different groups of animals may receive different doses of the test compound or drug being investigated. This allows researchers to assess the anxiolytic effects of the compound by observing any changes in climbing behavior compared to the control group.
• Data Analysis: The recorded latencies are analyzed statistically to determine the effects of the test compound. If the compound exhibits anxiolytic activity, it is expected to reduce the latency to climb the pole, indicating a decrease in anxiety-like behavior.
• Other Parameters: In addition to latency, researchers may also assess other parameters such as the number of climbing attempts, total climbing time, or behavioral changes observed during the test sessions. These additional measurements provide further insights into the effects of the test compound on anxiety-related behavior.

It is used to study anxiolytic activity in rats and mice. The basic principles of pole climbing apparatus are based on a neuro-chemical mechanism of anxiety disorders drugs like benzodiazepam are used.

Analgesiometer:

An analgesiometer is a device used in pharmacology labs to measure and quantify the level of pain sensitivity or analgesic (pain-relieving) effects of substances. It is a valuable tool for studying the efficacy of analgesic drugs and evaluating their potential therapeutic effects.

The analgesiometer typically consists of the following components:

• Paw Stimulator: The paw stimulator is a mechanical or thermal device that delivers controlled and calibrated pain stimuli to the animal’s paw. It can apply pressure, heat, or other forms of pain-inducing stimuli to the paw, mimicking the experience of pain.
• Reaction Measuring System: This system records and measures the animal’s response to the pain stimuli. It usually includes sensors or detectors that monitor specific behavioral or physiological responses, such as paw withdrawal, licking, or vocalization. These responses indicate the level of pain experienced by the animal.
• Data Acquisition and Analysis Software: To collect and analyze the data, an analgesiometer is often connected to a computer or data acquisition system. The software allows researchers to monitor and record the animal’s responses and analyze the results accurately.
• Experimental Chambers: The analgesiometer may include individual experimental chambers or compartments where animals are placed during the experiment. These chambers provide a controlled and standardized environment for conducting the pain sensitivity tests.
• Variable Parameters: Depending on the specific design and purpose of the analgesiometer, it may allow researchers to adjust and control various parameters, such as the intensity and duration of the pain stimuli, the intervals between stimuli, and the mode of delivery (mechanical, thermal, etc.).
• Animal Restraint Devices: To ensure the safety and stability of the animals during the experiment, analgesiometers may incorporate animal restraint devices. These devices secure the animal’s position and prevent excessive movements that could interfere with the accuracy of the pain response measurements.

It is used to study the analgesic effects of drugs in mice and rats. The inducer of pain such as heat, physio compression and chemical inducers. The basal reaction time was noted as an inference of pain sensation drugs like morphine and other NSAIDs are used.

Metabolic cage:

In pharmacology labs, a metabolic cage, also known as a metabolism cage or an excreta collection system, is a specialized apparatus used to study the metabolic processes and excretion of drugs or other substances in laboratory animals, typically rodents. Here are some key points about metabolic cages:

• Purpose: Metabolic cages are designed to facilitate the collection and separation of various excretory products (such as urine and feces) from laboratory animals. These cages allow researchers to measure and analyze the metabolic and excretory pathways of drugs, drug metabolites, and other substances of interest.
• Design: Metabolic cages are typically made of clear or translucent plastic and are designed to accommodate a single animal at a time. The cages are usually equipped with a raised platform or mesh floor to separate feces from urine, enabling separate collection of these excreta. The cages also have a feeding area and a water bottle or sipper tube for easy access to food and water.
• Collection of Excreta: The primary purpose of metabolic cages is to collect urine and feces separately. The urine is collected in containers placed below the cage floor or through a funnel system that directs it into a collection vial. Feces are collected in a separate container placed underneath the mesh floor or through a separate opening in the cage.
• Housing and Monitoring: Metabolic cages are often part of larger animal housing systems or racks, allowing multiple cages to be housed in a compact and controlled environment. The cages are usually equipped with sensors or monitoring devices to measure various parameters such as temperature, humidity, and lighting conditions. This helps maintain optimal conditions for the animals during experiments.
• Sample Analysis: After collection, the urine and feces samples can be analyzed using various techniques to determine drug concentrations, metabolite profiles, or other relevant parameters. Analytical methods may include chromatography, spectrophotometry, immunoassays, or other biochemical assays, depending on the specific substances being studied.
• Applications: Metabolic cages are widely used in pharmacology and toxicology research to assess drug metabolism, pharmacokinetics, and excretion patterns in laboratory animals. They provide valuable data on the absorption, distribution, metabolism, and excretion (ADME) of drugs and aid in understanding their pharmacological properties and potential toxicity.
• Ethical Considerations: The use of metabolic cages in animal research is subject to ethical guidelines and regulations to ensure the welfare and humane treatment of laboratory animals. Researchers must adhere to institutional animal care and use protocols, ensuring proper housing, handling, and care of the animals during the study.

Pharmacology I Practical

• Introduction to experimental pharmacology.
• Commonly used instruments in experimental pharmacology .
• Study of common laboratory animals .
• Maintenance of laboratory animals as per CPCSEA guidelines.
• Common laboratory techniques.
• Study of different routes of drugs administration in mice/rats .
• Study effect of hepatic microsomal enzyme inducers on phenobarbitone sleeping time in mice.
• Effect of drugs on ciliary motility of frog oesophagus
• Effect of drugs on rabbit eye.
• Effects of skeletal muscle relaxants using rota-rod apparatus .
• Effect of drugs on locomotor activity using actophotometer.
• Anticonvulsant effect of drugs by MES and PTZ method.
• Study of stereotype and anti-catatonic activity of drugs on rats/mice.
• Study of anxiolytic activity of drugs using rats/mice.
• Study of local anesthetics by different methods

Second Year B Pharm Notes , Syllabus, Books, PDF Subjectwise/Topicwise

Suggested readings:

• BP408P Pharmacology I Practical
• Structure and functions of Cell Human Anatomy and Physiology Notes
• Qualitative analysis of carbohydrates: Glucose (Unknown Sample)
• DETAILED STUDY OF FROG BY USING COMPUTER MODELS
• BP810ET Experimental Pharmacology Theory

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Virtual Pharmacology Lab

The Virtual Pharmacology Lab repository was designed to provide undergraduate teachers of pharmacology and related subjects with access to a wide range of electronic resources for teaching.

The Virtual Pharmacology Lab repository was designed to provide undergraduate teachers of pharmacology and related subjects with access to a wide range of electronic resources for teaching. It provided resources from a range of simulations of laboratory experiments involving isolated tissue preparations, in vivo animal preparations and some human experiments. Resources included:

• data traces of the effects of a wide range of pharmacological agents administered either alone or in combination with other agents
• animations, images and textual descriptions of the preparations, the experimental methods, and the underlying physiology, pharmacology and pathology

This project was developed by Dr. David Dewhurst at the University of Edinburgh.

The project has now been terminated since most of the items were built to run under Flash. Please click here for a list of Dr. Dewhurst's other resources. 

Other pharmacology simulations

Sheffield BioScience Programs, Dr. David Dewhurst

• Address: North Ferriby HU14 3JQ UK
• Email: [email protected]
• Web: http://www.sheffbp.co.uk/

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