Introduction to Pharmacology

• The presentation introduces pharmacology and describes the basic principles defining how drugs act in the body.
• It aims to provide a better understanding of pharmacology, drugs, and the role of pharmacologists.
• Focus on how pharmacologists determine drug actions and understand the relevance of this knowledge to prevent and treat diseases, as well as the balance between beneficial and harmful drug effects.

Pharmacology Explained

• Pharmacology is the study of the actions of certain chemicals on the functions of living systems.
• Mechanisms of action are the biochemical interactions through which a drug produces its pharmacological effect.
• Pharmacologists are most interested in drug actions and their relationship to normal or abnormal cell and tissue function.
• Drugs, defined as "certain chemicals," are the main tools of pharmacologists.

Scope of Pharmacology

• Pharmacology covers the study of chemicals that are exogenous (introduced from outside the body) and endogenous (present inside the body).
• Antibodies, enzymes, and hormones can be considered drugs and investigated for their therapeutic value.

Pharmacodynamics

• Pharmacodynamics refers to the actions of a drug molecule on the cells and tissues of the body.
• Pharmacology assumes a relationship between the dose of a substance and the body's response.
• An excessive dose of a drug will result in poisoning.

Pharmacokinetics

• There is a relationship between the dose of a drug and the body's response.
• The time course during which a drug remains at a sufficiently high concentration in its target tissues is important.
• Pharmacokinetics studies the absorption, distribution, metabolism, and excretion of drugs.

Drug Naming and Classification

• Drug names vary among the European English-speaking world, non-English-speaking European countries, and North America.
• Always verify accepted names from a suitable reference source.
• Changes in non-proprietary names are agreed upon by the EU, and a Recommended International Non-Proprietary Name (rINN) is used.
• rINN details can be found in the British National Formulary.
• International Non-Proprietary Names are generally preferred over chemical names in pharmacology.
• Drugs are grouped into classes according to their pharmacological and principal therapeutic actions.

Cell Structure and Function

• Cells, the smallest known living unit, are capable of maintaining and reproducing themselves.
• Cells from simple to complex life contain a similar basic structure and share nutritional requirements.
• A generic cell model can represent all cells.
• Understanding cell structure and function is essential to understanding how drugs act, which diseases can be treated with drugs, and why drugs sometimes cause side effects and toxicity.

The Cell Membrane

• Each cell is surrounded by a membrane.
• Act as a selective barrier that controls what enters and exits the cell (selective permeability).
• Holds and shapes the cell contents.
• Acts as a point of attachment to other cells.
• Consists of lipids, proteins and carbohydrates.

Lipids in the Cell Membrane

• Lipids, especially phospholipids, are most abundant and responsible for the hydrophobic nature of the cell membrane.
• Phospholipids have a hydrophilic head and a hydrophobic tail.
• Orientate with hydrophilic heads outermost, in contact with the aqueous environment, and hydrophobic tails innermost.
• Form bilayer sheets in cell membranes.

Proteins in the Cell Membrane

• A wide range of proteins is contained in the lipid bilayers.
• Proteins can be bound to the outer surface, have partly exposed regions, be buried in the hydrophobic layer, or extend right through the membrane.
• Perform functions such as recognition, transportation, attachment, and catalysis.

Carbohydrates in the Cell Membrane

• Carbohydrates attach to lipids or proteins in the cell membrane.
• Present as polysaccharides with hydrophilic chains.
• Orientate themselves away from the membrane surface on the outer surface.
• Confer a negative charge on the outer surface.
• Play a role in cell recognition.

Membrane Movement

• Cell membranes are not static in organization or fixed in composition.
• There is considerable lateral movement within the membrane and some membrane components get frequently re-cycled.
• Act as a highly organized, responsive frontier that exhibits selective permeability.

Cell Contents: DNA

• The principal component of the genetic material is deoxyribonucleic acid (DNA), often seen as chromosomes.
• In complex organisms, the nucleus is surrounded by phospholipid membranes and contains DNA, proteins, and a body known as the nucleolus.

Cell Contents: Nucleolus

• The main function of the nucleolus is to control the synthesis of ribonucleic acid (RNA) subsequently controlling the production of proteins.

Cell Contents: Mitochondria

• Mitochondria, enclosed by a phospholipid membrane, contains a high concentration of enzymes.
• They produce energy in the form of adenosine triphosphate (ATP), which is used by cells to drive essential reactions and processes.

Cell Contents: Endoplasmic Reticulum

• The largest organelle in the cell and takes the shape of a network of interconnected vesicles.
• There are two types of endoplasmic reticulum, smooth and rough, with different microscopical appearances.

Cell Contents: Endoplasmic Reticulum (Smooth)

• Smooth endoplasmic reticulum contains enzymes for the synthesis and metabolism of fatty acids and phospholipids, as well as the metabolism of many foreign chemicals.

Cell Contents: Endoplasmic Reticulum (Rough)

• Rough endoplasmic reticulum consists of a membrane studded with Ribosomes.
• Ribosomes facilitate protein synthesis, and the rough endoplasmic reticulum produces membrane proteins and some proteins secreted from the cell.

Cell Contents: Golgi Body

• The Golgi body, a phospholipid membrane-bounded organelle transfers, sorts, and modifies many of the cell's proteins, particularly from the rough endoplasmic reticulum.

Cell Contents: Lysosome and Peroxisomes

• Both are membrane-surrounded organelles that contain specific enzymes to degrade proteins, lipids, carbohydrates, RNA, and DNA.
• Lysosomes break down cellular materials and sometimes entire organelles like mitochondria. - The resulting smaller molecules can be metabolized and used within the cell.

Cytoplasm

• Cytoplasm fills the space between cell structures.
• It consists of a viscous fluid with ions, dissolved small molecules, and networks of fibers.
• These fibers form the cytoskeleton, divided into microtubules, microfilaments, and intermediate filaments.
• Microtubules are assembled from tubulin proteins.
• Microfilaments contain protein actin, and form bundles and three dimensional intracellular meshwork in cells.
• Intermediate filaments are elements that are composed of intermediate filament proteins, and their size lies within a range in-between microtubules and microfilaments.

Eukaryotic and Prokaryotic Cells

• Plants and bacteria have a cell wall outside the plasma membrane for strength and rigidity.

Cell Division

• Growing cells can duplicate their DNA and pass an identical copy to a new cell.
• This process, known as mitosis in eukaryotic cells, involves DNA replication and chromosome separation into two identical copies.
• The cell membrane constricts, resulting in two identical cells from the original cell.
• During reproduction, genetic material is paired from different sources.
• Each chromosome is divided when eggs and sperm are formed during meiosis.
• Eggs and sperm contain half the number of chromosomes compared to other cells.
• Fertilization results in the formation of a new cell with a full set of chromosomes and differing genetic constitution.

Cell Differentiation

• Cells contain the same genetic material, but they express different genes allowing for form and functional differences (nerves, kidney cells, and muscle cells).
• The groups of cells forming tissues remain bound by protein-based adhesion molecules and commit to a specific type.
• These cells migrate during the embryo development.
• They take up particular positions with respect to other groups of cells.
• Cells differentiate and progressively change the production patterns of their proteins to match the mature cells.
• Some changes such as completing the protein makeup can take longer than others.

Tissues, Organs, and Extracellular Matrix

• Tissue can be described as a mass of cells that carry out specified functions.
• Organs are formed from differing types of tissue arranged within specified anatomical arrangements facilitating critical functions.
• The main tissue types include epithelial, connective, nervous, and muscular tissue.
• In some organs there is a considerable divide between the individual cells.
• This space and the fibres are known as the extracellular matrix, that allows for diffusion of small molecules and binding of collagen and elastin fibres.

Cell Function and Disease

• Homeostasis involves maintaining the internal environment within the body.
• Pathology describes the deviation from normal cellular function.
• The disease is a pattern of changes that sufficiently impairs normal body activities.
• The disruption of cellular function is caused by internal factors (genes) or external (dietary, chemical, physical etc.)

Selective Drug Action

• Variations amongst cell biochemistry and structure, even within an organism, create the opportunity for selective drug actions.
• Effective selective action is rooted in the highly regulated systems that coordinate cellular function and integrate bodily processes.