Pharmacodynamics I - Darmani

Question 1

Covalent bond

Answer 1

• Two atoms sharing electrons

* Cannot be separated

Question 2

Ionic bond

Answer 2

• Forces between charged ions

* Can be separated

Question 3

Hydrogen bond

Answer 3

Special kind of ionic bond

Question 4

Van der Waals bond

Answer 4

• Weakest of all bonds

* The attractive forces between non polar molecules

Question 5

Agonist

Answer 5

An agent that binds a receptor (orthosteric site) and produces a signal

Question 6

Allosteric site

Answer 6

The region of the receptor where allosteric modulators bind

Question 7

Antagonist

Answer 7

An agent that binds a receptor and prevents the agonist from producing an effect

Question 8

What are the 4 different receptor superfamilies?

Answer 8

1. Receptors coupled to ion channels
2. G-protein coupled receptors
3. Enzyme-linked receptors
4. Intracellular receptors

Question 9

Receptors coupled to ion channels

Answer 9

• Aka ionotropic receptors
• Control the fastest synaptic events
• Include: ligand gated and voltage gated channels
• Large extracellular N-terminal
• 4 transmembrane helices
• Short extracellular C-terminal

Question 10

G-protein coupled receptors

Answer 10

• Aka metabotropic receptors
• Consist of 7 transmembrane and 4 intracellular domains
• Extracellular N-terminal
• Intracellular C-terminal
• Dimerization may regulate the affinity and specificity of the complex for G proteins, and regulate the sensitivity of the receptor to phosphorylation

Question 11

Enzyme-linked receptors

Answer 11

• Mediate the actions of a variety of growth factors, cytokines and insulin
• 2 most important pathways for these receptors:
1. Ras/Raf/mitogen activated protein (MAP)
2. Jak/Stat pathway

Question 12

Intracellular receptors

Answer 12

• Aka steroid receptors
• C-terminal contains receptor site to which lipid soluble hormones or drugs bind to
• N-terminal control gene transcription

Question 13

Type I Intracellular receptors

Answer 13

• Include targets for sex hormones (androgens, estrogen & progesterone receptors), glucocorticoid receptors and mineral corticoid receptors
• Steroid receptors are located in the cytoplasm and bound to accessory heat-shock protein
• Activated by steroids that can diffuse through the cell membrane

Question 14

Type II Intracellular receptors

Answer 14

• Include thyroid hormone, vitamin A and D receptors and retinoid receptors
• Activated by the ligand entering the nucleus through nuclear pores
• Once activated there is a conformational changes that exposes the normally hidden DNA-binding domain
• After the DNA binding, there is an increase in RNA polymerase activity and the production of specific mRNA
• The response can take hours to days