Lecture 2 Flashcards
What does Pharmocodynamics and Pharmokinetics focus on ?
Pharma kinetics
- Dosage and Plasma concentration
Pharmacodynamics
- Site of action and effects
What is a receptor ?
A macromolecular component of the organism that
binds the drug and initiates its effect.
They are chemical structures
What are Most receptors ?
Most receptors are proteins that have undergone various
post-translational modifications such as covalent
attachments of carbohydrate, lipid and phosphate.
What are the 4 things that Regulate Cell function ?
Regulate cell function by altering
- Enzyme activity
- Permeability to ions
- Conformational features
- Genetic material
How is Enyme activity regulated ?
The signaling molecule binds to the receptor on the outside of the cell and causes a conformational change on the catalytic function located on the receptor inside the cell.
Examples of the enzymatic activity include: Receptor tyrosine kinase, as in fibroblast growth factor receptor.
Genetic Material
Genetic materail have a greater impact
Conformational Features
Binding of receptors can have an affect on there change
What are the three main features of Receptors ?
Selectivity: binding of drugs to receptors depends
on physico-chemical structure.
• Affinity: strength of binding between the drug&
receptor.
• Efficacy/Intrinsic activity: ability of a drug to
elicit a pharmacological response after its
interaction with receptor
Agonists of Cell Surface Receptors
e.g. alpha-agonists, morphine agonists
These receptors activate a G protein upon agonist binding, and the G-protein mediates receptor effects on intracellular signaling pathways.
Alpha agonists -
selectively stimulates alpha adrenergic receptors. The alpha-adrenergic receptor has two subclasses α1 and α2. Alpha 2 receptors are associated with sympatholytic properties.
Agonists of Agonists of Nuclear Receptors (e.g. nitroglycerine (guanylyl cyclase), pralidoxime, acetylcholinesterase)
Agonists. The activity of endogenous ligands (such as the hormones estradiol and testosterone) when bound to their cognate nuclear receptors is normally to upregulate gene expression. This stimulation of gene expression by the ligand is referred to as an agonist response.
Enzyme Activators
Enzyme activators are molecules that bind to enzymes and increase their activity. They are the opposite of enzyme inhibitors. These molecules are often involved in the allosteric regulation of enzymes in the control of metabolism.
Ion Channel Openers (e.g. minoxidil (K), vasodilator; and alprazolam (Cl) antipsychotic drug)
A channel opener, also known as a channel activator, is a type of drug which facilitates ion flow through ion channels.
These drugs below are examples of the faciliation of channels
Antopsychotic drug - Antipsychotics help to control the symptoms of psychosis as well as less serious mental health conditions such as bipolar and mood disorder that may develop into later psychosis. Antipsychotics reduce or increase the effect of neurotransmitters in the brain to regulate levels.
Vasodilator and alprazolam - Vasodilators are medicines that dilate (widen) blood vessels, allowing blood to flow more easily through. Some act directly on the smooth muscle cells lining the …
Alprazolam It can treat anxiety and panic disorder.
Minoxidil is a potassium channel opener, causing hyperpolarization of cell membranes. Theoretically, by widening blood vessels and opening potassium channels, it allows more oxygen, blood, and nutrients to the follicles.
Receptor ligand interaction
Molecules (eg, drugs, hormones, neurotransmitters) that bind to a receptor are called ligands. The binding can be specific and reversible. 9 Locak adKey)A ligand may activate or inactivate a receptor; activation may increase or decrease a particular cell function. Each ligand may interact with multiple receptor subtypes.
Induces conformational change in
receptor protein
– Leads to change within cell
What are some characteritics of Drug receptors?
Chemical Bond: ionic, hydrogen, hydrophobic, Van der Waals, and covalent. • Saturable • Competitive • Specific and Selective • Structure-activity relationships • Transduction mechenasims
Receptor Transduction Mechanisms
majority of signal transduction pathways involve the binding of signaling molecules, known as ligands, to receptors that trigger events inside the cell.
The binding of a signaling molecule with a receptor causes a change in the conformation of the receptor, known as receptor activation.anisms
is defined as the ability of a cell to change behaviour in response to a receptor-ligand interaction.
The ligand is the primary messenger.
