Brief history of Pharmacology

In my past entry I explained what is pharmacology and the difference between it and pharmacy. Both started as the same discipline, but over time they grew slightly apart. This gives us an interesting question.

For how long has pharmacology been around?

Well, it can be said that pharmacology started in prehistoric times, when our ancestors desperately looked around for ways to treat their injuries or illnesses, they looked in the natural world and by trial and error, over time they found that some herbs and minerals had an effect which could be helpful; of course, most of the things they tried might not have had an effect at all or probably worse, they could have been very toxic to them. For a long time all this knowledge was gathered through trial and error, and many hypotheses were formulated to explain how these compounds extracted from herbs or minerals were curing or treating illnesses.

For a long time it was believed that everything was made of 4 primordial elements and that every substance had them in different proportions; following this idea, they tried to explain that medicines somehow changed the proportions of these elements in the body, restoring them to a natural balance. For example, it was thought that fever was caused by excess in fire element; therefore substances that lowered the fever were thought to have a large amount of the water element.

A different hypothesis came from the Greek physicians Hippocrates and Galen who thought that illness was caused by imbalances in four “humors” in the body and that medicines had the effect of altering the balances in humors hence restoring health to the body. Other explanations were those given by the alchemists, which believed that astrological events and metals were associated with the function of the different organs in the body, and by giving compounds that contained metals in different proportions would restore function to the affected organs.

These ideas were attempts at understanding how medicines had an effect in the body but they were severely limited by the knowledge available in those times; it was not until the 18th century when modern chemistry was systematized by Lavoisier, that a different way of looking at medicines was developed. Medicines were not seen in a mystical or magical context anymore. They were seen as chemical compounds that interacted with other compounds to give products. Thanks to this idea scientists began thinking that the interactions between medicinal compounds and the organisms were the result of chemical reactions that altered the functions of cells and tissues.

During the 19th century, the advances in chemistry gave place to the identification and synthesis of active substances in medicines, which traditionally were prepared from plants. This allowed for the mass production of synthetic drugs, setting the basis for what now is the pharmaceutical industry.

The advent of synthetic drugs, as well as the new discoveries on human physiology, which explained biological processes as results of complicated chemical interactions, helped define modern pharmacology. Oswald Schmiedeberg in the late 19th century is recognized as the founder of modern pharmacology, he began studying how chloral hydrate and chloroform performed their actions in animals, and relating its administration with physiological modifications. In 1878 he published a classic text, “Outline of Pharmacology”, which became the basis for most modern pharmacology books.

The 20th century introduced a new concept in pharmacology, the idea that a drug interacts with a target molecule or “receptor” inside the organism, these receptors (usually proteins found in the membranes of cells or domains in enzymes and proteins) undergo chemical changes when the drug is bound to them, and these chemical changes activate a cascade of biochemical reactions which in turn happen to change the functions of cells. A great bacteriologist and chemist Paul Erlich proposed this concept. From this concept, a multitude of receptors have been discovered as well as drugs that can either activate these receptors or block them.

All these advances have given place to what is known as rational design of drugs. By knowing how specific receptors when activated exert a response in the body, molecules can be designed to interact specifically with them; an example of this is Captopril, developed by M. Ondetti and co-workers at Squibb Laboratories in the 1970s, this molecule was rationally designed to fit the active site of the angiotensin converting enzyme (ACE). Which converts Angiotensin I to Angiotensin II, a potent vasoconstrictor that increases blood pressure. This drug blocks the activity of the enzyme decreasing the blood pressure in patients with hypertension. This development gave birth to a generation of ACE inhibitors, introducing a new therapy for reducing blood pressure.

This is a very brief history of pharmacology, it is important to understand how its study has given new insights in the physiology of the organism, as well as new and improved treatments for the different illnesses that affect the human body.

Thank you for reading!