Receptor pharmacology 2018/2019
➔ Receptor pharmacology
→ Section 1: General pharmacological
principles
Pharmacology = interactions of
chemical substances (drugs) with the
living organism.
Drug = chemical applied to a
physiological system that affects its
function in a specific way.
Pharmacokinetics = the study of the
time course of drug absorption,
distribution, metabolism, and excretion.
Pharmacodynamics = the quantitative study of the relationship between drug exposure
(concentrations or dose) and pharmacologic or toxicologic responses. The mode of action of drugs.
Pharmacodynamics is closely related to pharmacology.
Specificity of drug actions:
- Non-specific: biological effect at relatively high drug concentrations (e.g. antacids, adsorbents,
osmotic agents).
- Specific: biological effect at relatively low drug concentrations, chemical and biological specificity.
Most drugs act on target proteins with high affinity to the drug. There is specificity in the ligand and
in the receptor.
Drugs act on target proteins:
- Receptors
- Ion channels
- Enzymes
- Carriers
Receptors are target molecules whose function is to recognize and respond to specific endogenous
chemical signals, such as hormones, neurotransmitters and inflammatory mediators. Receptors are
important for cell communication!
Reciprocal specificity of receptor-drug interaction: individual classes of drugs bind to discrete
receptors, while individual receptors recognize only discrete classes of drugs. High specificity by high
affinity. However, no drugs are completely specific in their
action. Side effects may occur at relatively high drug
concentrations, due to other targets (receptors) with lower
affinity.
Agonists and antagonists
Distinction between drug binding and receptor activation:
agonists and antagonists.
Agonist: receptor occupation leads to biological response.
Antagonist: receptor occupation does not lead to response
and prevents the effect of an agonist, mostly by preventing it from binding.
The agonist is capable of reinforcing the active state, the antagonist is not. The antagonist prevents
activation by the agonist.
1
➔ Receptor pharmacology
→ Section 1: General pharmacological
principles
Pharmacology = interactions of
chemical substances (drugs) with the
living organism.
Drug = chemical applied to a
physiological system that affects its
function in a specific way.
Pharmacokinetics = the study of the
time course of drug absorption,
distribution, metabolism, and excretion.
Pharmacodynamics = the quantitative study of the relationship between drug exposure
(concentrations or dose) and pharmacologic or toxicologic responses. The mode of action of drugs.
Pharmacodynamics is closely related to pharmacology.
Specificity of drug actions:
- Non-specific: biological effect at relatively high drug concentrations (e.g. antacids, adsorbents,
osmotic agents).
- Specific: biological effect at relatively low drug concentrations, chemical and biological specificity.
Most drugs act on target proteins with high affinity to the drug. There is specificity in the ligand and
in the receptor.
Drugs act on target proteins:
- Receptors
- Ion channels
- Enzymes
- Carriers
Receptors are target molecules whose function is to recognize and respond to specific endogenous
chemical signals, such as hormones, neurotransmitters and inflammatory mediators. Receptors are
important for cell communication!
Reciprocal specificity of receptor-drug interaction: individual classes of drugs bind to discrete
receptors, while individual receptors recognize only discrete classes of drugs. High specificity by high
affinity. However, no drugs are completely specific in their
action. Side effects may occur at relatively high drug
concentrations, due to other targets (receptors) with lower
affinity.
Agonists and antagonists
Distinction between drug binding and receptor activation:
agonists and antagonists.
Agonist: receptor occupation leads to biological response.
Antagonist: receptor occupation does not lead to response
and prevents the effect of an agonist, mostly by preventing it from binding.
The agonist is capable of reinforcing the active state, the antagonist is not. The antagonist prevents
activation by the agonist.
1
