ABSORPTION
DISTRIBUTION
Drug in tissues
Drug in systemic circulation
Pharmacokinetics
Drug metabolized or excreted
ELIMINATION
Drug at site of action
Pharmacologic effect Pharmacodynamics Toxicity Efficacy
PHARMACOLOGY Pharmacodynamics
Actions of drug on the body Specific to a drug/ class of drugs • Interaction with target sites (receptors/enzymes) • Effects at site of action • Dose-response relationship • Reduction in symptoms • Modification of disease process • Unwanted/side effects • Drug interactions • Inter- and intra-patient differences
Pharmacokinetics
Actions of body on the drug Non-specific, general processes • Absorption from site of administration • Distribution to the …show more content…
Rested
Non-conducting
Closed but openable in reponse
to appropriate stimulus
Activated (open) 3. Inactivated
2.
Closed and unable to open in
response to appropriate stimulus for rested state channel
When ligand binds to the ligand-binding site Conformation change in other parts of ROC molecule Opening of central, ion-selective pore Increase transmembrane conductance Alters electrical potential across the membrane Transmits signal across plasma membrane
Acetylcholine binds to the nicotinic acetylcholine receptor
Opening of ion channel Allows Na+ to flow down its
concentration gradient into cells Produce a localised excitatory postsynaptic potential (a depolarization)
Similar to ROC But operated by voltage, instead of ligands Examples:
Cardiac Na+ channel Ca2+ selective VOC K+ selective VOC
Cellular response occur in the range of milliseconds after binding of agonist to a ligand-gated channel
(4) G-Protein Coupled Receptor
Receptor located on cell membrane G protein
› A complex of 3
subunits (α, β and γ) › A transduction component › Energy dependent (ATP, GDP)
In the rested state (When no ligand is present)
G protein o Subunits are bound together o GDP (Guanine nucleotide diphosphate) is tightly bound to the α subunit of the G protein
G protein in this