General Pharmacodynamics

Question 1

when a substance is administered in a biological system, the effect is dependent on

Answer 1

concentration of the drug in the system or dose

Question 2

The dose represents

Answer 2

amount of drug administered in that biological system

Question 3

The representation of the intensity of the effect as a function of dose curve corresponds to
a certain mathematical relation according to which:

Answer 3

E = ( D X Emax ) / ( D + DE50 )
where E = the effect,
D = the dose (or concentration) of the substance,
Emax = the maximum effect that can be obtained in the respective biological system, and
DE50 represents = the dose that produces half (50%) of the maximum effect that can be obtained in that system

Question 4

Evolution of the intensity of the effect of a drug on a biological system,
depending on

Answer 4

dose administered (dose / effect relationship)

Question 5

endogenous

molecules with specific affinity for drugs are called

Answer 5

receptor molecules or

pharmacological receptors

Question 6

Ka: affinity constant :

Answer 6

Ka = K1 / K2

Question 7

Kd : dissociation constant :

Answer 7

Kd = K2 / K1

Question 8

potency of a

drug is all the greater as

Answer 8

lower dose is required to achieve a certain intensity of effect.

Question 9

In pharmacological practice the assessment of the potency of a drug is made taking into
account the

Answer 9

value of the dose that produces half of the maximum effect, a dose usually noted with DE50. The lower the DE50, the higher the potency of the drug

Question 10

A certain substance, in order to produce a certain effect on a biological system,
must have two properties :

Answer 10

1) Affinity

2) Intrinsic activity

Question 11

affinity

Answer 11

the ability of the substance to bind to

pharmacological receptors

Question 12

intrinsic activity

Answer 12

the ability of the substance to activate

those receptors so as to produce a certain effect

Question 13

agonists

Answer 13

Substances with affinity and intrinsic activity to certain pharmacological receptors are called agonists

Question 14

antagonists.

Answer 14

Substance b has an affinity for the receptors but it has no intrinsic activity

Question 15

Partial agonists

Answer 15

produce concentration-effect curves that resemble those observed with full agonists in the presence of an antagonist that irreversibly blocks some of the receptor sites
- Partial agonists have intrinsic activities greater than zero but less than one

Question 16

Depending on their morphofunctional structure, 4 major types of pharmacological
receptors have been described :

Answer 16

• Ionic channels
• G protein coupled receptors
• The enzymatic receptors
• Nuclear receptors

Question 17

Ionic channels

Answer 17

transmembrane structures consisting of 4 or 5 transmembrane subunits that surround a pore through which a particular species of ion can specifically
penetrate. Depending on the ion that can cross the ion channel, sodium channels,
potassium channels, calcium channels, chlorine channels, etc. have been described.

Question 18

G protein-coupled receptors

Answer 18

• most widespread receptors in the
  body
• consist of 7 transmembrane segments
• joined together by 3 extracellular loops and 3 intracellular loops
• having a free extracellular
• initial portion and a free intracellular terminal portion
• The receptor drug binding site is located extracellularly and usually involves the transmembrane SIII segmen
• Sometimes, along with the SIII segment, the SIV or SV segment or even all three SIII, SIV and SV
  segments is involved.
• The third intracellular loop, which joins the SV and SVI
  transmembrane segments, is coupled to a specific structure called the G protein.

Question 19

3 types of G proteins were described, marked with Gs, Gi and Go. Gs and Gi
modify the function of

Answer 19

adenylate cyclase, the former stimulating its activity (s from stimulation), the latter inhibiting it (i from inhibition).

Question 20

Go proteins stimulate

Answer 20

activity of phospholipase C and releases calcium from

intracellular deposits in the endoplasmic reticulum

Question 21

The enzymatic receptors

Answer 21

• consist of a transmembrane portion,
• usually small in size,
• which joins an extracellular portion and an intracellular portion, which are relatively
  large.
• Sometimes these receptors are in dimeric form, as is the case with insulin receptors.

Question 22

Nuclear receptors

Answer 22

• are intracellular structures consisting of 2 subunits: an effector subunit and a regulatory subunit with inhibitory role.
• The receptor-subunit effector subunit complex penetrates the nucleus and modifies the synthesis processes of enzymatic proteins