Instruments of Experimental Pharmacology

Instruments

Experimental pharmacology involves using various instruments and equipment to study the effects of drugs on living organisms. Some commonly used instruments in experimental pharmacology include:

  • Organ Bath Assembly
  • Rota-rod Apparatus
  • Actophotometer
  • Electroconvulsiometer
  • Elevated plus maze

Organ Bath Assembly

An organ bath assembly is a laboratory apparatus used in pharmacology experiments to study the effects of drugs on isolated organs. It is used to study isolated tissue preparations' contractile or relaxation responses in response to different drugs or stimuli. 

The assembly consists of a water-jacketed glass chamber (an inner organ tube), a temperature control unit, a tissue holder or aeration tube, a force transducer (or a writing lever), and a data acquisition system (or a Sherrington rotating drum to place a kymograph).

The tissue to be studied is usually isolated from an animal and mounted on a tissue holder. The tissue holder is then suspended in the inner organ tube, which is filled with oxygenated physiological salt solution maintained at a constant temperature using the temperature control unit.

The force transducer, connected to the tissue holder, measures the force generated by the tissue in response to different drugs or stimuli. The data acquisition system records and analyzes the data generated.

Organ bath assembly is a versatile tool used to study a wide range of tissues, including smooth muscle preparations from the gastrointestinal tract, respiratory system, and blood vessels. It can also be used to study cardiac and skeletal muscle preparations.

Rota-rod Apparatus

The Rota-rod Apparatus is a commonly used instrument in experimental pharmacology to evaluate animal motor coordination and balance. It consists of a rotating rod, usually made of plastic or metal, that is suspended above a base platform. 

The rod rotates at a fixed speed, and the animal is placed on the rod and allowed to walk or run. The time the animal remains on the rod before falling off is recorded as a measure of its motor coordination and balance.

Fig. Rota-rod Apparatus

This apparatus is especially useful for assessing the effects of drugs or other treatments on motor function in animals. It is often used in research related to Parkinson's disease, stroke, and other neurological disorders that affect motor function. 

The Rota-rod Apparatus can also be used to study the effects of environmental factors such as aging or stress on motor function.

Actophotmeter

An Actophotometer is a device used in experimental pharmacology to measure the activity level and behavioral responses of laboratory animals such as mice and rats. It consists of an enclosed chamber equipped with photoelectric sensors that detect the animal's movement and translate it into digital signals.

Fig. Top view of Actophotometer

The animal is placed inside the chamber, and its activity is monitored by the photoelectric sensors. The sensors detect the movement of the animal, such as running, walking, or jumping, and the data is collected and recorded by a computer connected to the Actophotometer.

The Actophotometer is used to study the effects of drugs or other substances on the animals' activity levels and behavioral responses. For example, it can be used to determine the effects of a drug on locomotor activity, exploratory behavior, or anxiety-like behavior.

Electroconvulsiometer

An electroconvulsiometer is a device used in experimental pharmacology to induce seizures in laboratory animals for research purposes. It is also known as an electroshock apparatus or shocker. The device works by delivering an electric current through electrodes placed on the animal's head, inducing a convulsive seizure.

The electroconvulsiometer consists of a power source, a stimulator, and electrodes. The power source provides the electrical current, while the stimulator controls the duration and intensity of the stimulus. The electrodes are placed on the animal's head and are used to deliver the electric shock.

The electroconvulsiometer is used in the study of epilepsy, depression, and other neurological disorders. It can also be used to test the efficacy of anticonvulsant drugs and other treatments.

Elevated Plus Maze

The Elevated Plus Maze is an apparatus used in experimental pharmacology to evaluate anxiety-like behavior in laboratory animals such as mice and rats. The apparatus consists of two open arms and two enclosed arms elevated from the ground, arranged in the shape of a plus sign. The open arms do not have any walls, while the enclosed arms have walls that the animal can hide behind. The animal is placed on the central platform and its behavior is recorded over a set period of time.

Fig. Top view of Elevated Plus Maze

The Elevated Plus Maze works on the principle that rodents are naturally inclined to avoid open and elevated spaces and prefer to stay in enclosed areas. Thus, the amount of time spent by the animal in the open arms versus the enclosed arms of the maze can be used to assess its level of anxiety.

The apparatus is typically used in the early stages of drug development to evaluate the anxiolytic potential of new drugs. It can also be used in preclinical research to study the neurobiological mechanisms of anxiety and to evaluate the efficacy of potential treatments for anxiety disorders.


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