What is Pharmacology?
Pharmacology is the study of how drugs exert their effects
on living systems. Drugs can be defined as chemical agents
that interact with specific target molecules, thereby producing
a biological effect. Pharmacologists work to indentify drug targets
in order to learn how drugs work. Pharmacologists also study the
ways in which drugs are modified within organisms. A fundamental
knowledge of the underlying biological processes is required to
achieve these objectives and to identify new targets for future
therapeutic intervention. Thus, pharmacologists study many basic
aspects of cellular and molecular biology.
In recent years, there has been a dramatic increase in the rate
at which novel drugs are discovered and marketed. As a consequence,
it is essential to train a new generation of pharmacologists who
will meet the challenges this opportunity presents.
Pharmacy, often confused with pharmacology, is a wholly
separate profession concerned with the preparation, dispensing
and use of medications. Whereas pharmacy can be viewed as a profession
that is part of health care delivery and information systems, pharmacology
is a basic biomedical scientific discipline.
Modern pharmacology is divided into
many specialties:
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Neuropharmacology
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Behavioral Pharmacology
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Cardiovascular Pharmacology
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Molecular Pharmacology
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| Neuropharmacologists engage in research
into the mechanism of action of drugs that affect the central
and peripheral nervous systems. As with most of the pharmacologic
specialties, drugs are also used as tools to gain insight into
both normal and abnormal function. |
Behavioral Pharmacologists study
the influence of drugs on higher cognitive functions, including
learning, memory, and addiction. |
Investigators in this area study
the mechanism of action of drugs used in the treatment of conditions
such as high blood pressure and cardiac failure. Experiments
are conducted both at the molecular level and in intact organisms. |
The techniques of molecular biology are applied
to address questions in pharmacology. Molecular cloning and
gene expression technology are applied both to cells in culture
as well as to intact organisms to identify new drug targets
and understand the molecular mechanism of action of drugs. |
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Clinical Pharmacology
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Chemotherapy
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Biochemical Pharmacology
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Specialties
not listed here include toxicology, pharmacogenetics, renal
pharmacology, and others. |
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Clinical pharmacology links basic pharmacology with the
goal of treating sick people or preventing sickness. Clinical
pharmacologists are interested in the actions of drugs in
humans at the molecular, sub-cellular, organ, and whole-body
levels.
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Pharmacologists in this area work
to understand the mechanism of action of agents that exhibit
selective toxicity, killing invading microbes or cancer cells,
while sparing those of the host. |
Methods used to study cell biology
and biochemistry are employed to gain insight into how therapeutic
agents influence the intracellular 'machinery of life'.
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What questions do pharmacologists ask?
- What mechanisms are responsible for drug tolerance and drug
addiction, and how are these manifested?
- What are the molecular targets for drugs? How do these agents
produce their effects?
- How does drug-resistance evolve in cancer cells and microbes?
- Can drugs be used to prevent conditions such as cancer, heart
disease and neurodegeneration?
- How does the body terminate the action of a drug?
- Can drugs that control obesity be developed?
- What causes aging? Can drugs reverse or retard this process?
- How are the electrical activities of the heart and brain controlled,
and how do drugs influence such activities?
A history of pharmacology
Ancient Times
The mists of antiquity shroud the early history of humankind's efforts to harness
the healing properties of natural compounds. However, it is known for certain
that ancient peoples made extensive use of plant, animal and mineral sources
for this purpose. The Ebers papyrus, thought to have been written in Egypt
in the 16th century B.C., lists the extensive pharmacopia of that
civilization. Included in this this are: beer, turpentine, myrrh, juniper
berries, poppy, lead, salt and crushed precious stones. Also included were
products derived from animals, including lizard's blood, swine teeth, goose
grease, ass hooves and the excreta from various animals. The effects of many
of these drugs on patients of antiquity can only be imagined. However, it
is doubtless that many successes were encountered.
From ancient China comes evidence of that culture's extensive
efforts to heal through the use of natural products. The Pen
Tsao, or Great Herbal, comprised forty volumes describing several
thousands of prescriptions. Interestingly, the eastern herb Artemisia
annua L. (wormwood), used in China since antiquity to treat
fevers, is the source of the modern drug qinghaosu, which
shows great promise as a modern anti-malarial compound.
Antiquity to the modern era
The ancients considered disease a consequence of demonic possession, or the
wrath of god. Thus, in ancient times, the treatment of illness with natural
products was invariably accompanied by religious rituals deemed essential
to the healing process. Eventually, there was a greater appreciation that
the natural products themselves held the power to cure. However, traditional
remedies still generally consisted of complex mixtures of distinct herbs
and minerals, perhaps only one (if any) of which possessed activity. For
example, the purple foxglove, Digitalis purpurea, was one of twenty
herbs used in a folk remedy to treat dropsy in 18th century England.
From the leaves of this plant was isolated the cardiac glycoside digitalis,
a drug still used today to treat heart failure.
Over time, as a more sophisticated view of illness evolved, an
increasingly scientific approach to the isolation of drugs from
natural products was taken. In the early 19th century,
morphine was isolated from the opium poppy (Papaver somniferum)
and the anti-malarial compound quinine from the bark of the cinchona
tree (Cinchona officinalis). These, and additional advances
in the fields of chemistry and physiology, lead to the birth of
modern pharmacology in the latter half of the 19th century.
Thus, the ancient discipline of Materia Medica, devoted
to understanding the origin, preparation and therapeutic applications
of medicinal compounds, has evolved into the experimental science
of pharmacology, which is devoted to understanding the physiological
action of these molecules. In America, this transformation was
marked by the creation of the American Society for Pharmacology
and Experimental Therapeutics (ASPET) in 1908.
The modern era
In 1897, Felix Hoffman, a reserach chemist employed by the "Farbenfabrikin
vorm. Freidr. Bayer and Co." synthesized acetylsalicylic acid. On February
1, 1899, Aspirin® was registered as a trademark. On March 6th of
the same year, this drug was registered with the Imperial Patent Office in
Berlin. Aspirin quickly become popular worldwide, and remains an important
drug today. (Interestingly, it was not until 1971 that Sir John Vane discovered
the mechanism of action of aspirin, a feat that earned him the 1981 Nobel Prize
for Medicine.) The 20th century has witnessed the discovery of a
steady stream of important new drugs that have immeasurably improved the human
condition. Indeed, it is difficult to imagine our world without these important
therapeutic agents. Not very long ago, vast numbers of humans perished prematurely
or suffered an existence filled with pain due to the effects of infection or
disorders that are now successfully treated. Progress has been particularly
noteworthy in the areas of chemotherapy of cancer and microbial infections,
a field that came into existence in this century. Likewise, we have made significant
progress in our ability to use drugs to treat chronic conditions, such as diabetes,
hypertension, and depression. It is hard to measure the contribution these
drugs have made to improve the human condition. However, as the recent AIDS
pandemic illustrates, at the dawning of the new millennium there remain many
significant challenges, as well as opportunities, for those interested in pursuing
a career in pharmacology.
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