Pharmacology lectures Flashcards
Specificity
specifity is the effect of a drug upon one individual pharmacological action.
Disassociation constant
disassociation constant is the concentration when half the drug binds to the receptor to form the drug receptor complex.
What is the central compartment?
Liver, kidneys and plasma, Areas that are highly perfused.
What is the peripheral compartment?
Muscle. Areas that are poorly perfused.
Affinity
Affinity is the strength of the covalent bonds between the drug and the receptor measured by the disassociation konstant Kc
Non specific binding
Non specific bidning is when drugs use plasma gobulins to produce an effect.
Potency
potentcy is the dosage of a drug needed to produce an effect at a given intensity.
Ec50
effective concentration/ec50 is the concentration of a drug needed to produce half the maximum effect.
Gs protein
Stimulates adenyl cyclase enzyme for cAMP formation
Gq protein
Activates phoshpolipase C which increases production of IP3 to release intracellular calcium and DMG for protein kinase activation to influence protein synthesis
Gi/Go protein
Inhibits adenyl cyclase enzyme to prevent cAMP formation
Action of tyrosine kinase
Tyrosine kinase autophosphorylates tyrosine residues on intracellular domain. It can then recruit G proteins to control gene expression.
Cytoplasmic receptors
in the cyptoplasm there are homodimers and the ligand is endocrine
Nuclear receptors
in the nucelus it is heterodimers and the ligand is usuallly a lipid
Trachphylaxis
trachyphylaxis is the usual timecourse of a drug in the formaiton of the complex and the time taken for the drug to leave the tissue. usually greater dosage can just be given.
Time course
Time taken for drug to bind to receptor and be removed from tissue
Ammonia hydroxide
Antipyretic for itching by lowering pH
Effect of alcohol
Increases fluidity of cells
St John’s wort
Anti depressant
Milk thistle
Treatment for liver dysfunction
Agonist treatment for opioid addiction
Methadone- analgesic which treats withdrawal symptoms
Antagonist treatment for opioids
Naltrexone- creates negative donitioning by preventing possitive effect
MAP kinase pathway
Ligand binding causes dimerisation. Kinase enzymes is activated and phosphorylates amino acid residues present on intracellular catalyctic domain. This activates the intracellular catalyctic domain. The GTPase Ras protein is activated which subsequently activates Map kinase kinase kinase through the use of a guanine exchange factor to substitute GDP for GTP. This then allows the activated map kinase kinase kinase to activate downstream map kinase kinase through the hydrolysis of ATP –ADP. Activated map kinase kinase activates downstream map kinase through ATP hydrolysis –> ADP which allows it to alter gene expression of proteins.
GTP
GTPase is activated by the binding of GTP caused by guanine exchange factors. GTPase is inactivated by GTPase regulatory proteins. GTPase regulatory proteins inhibit GTPase in response to GTP hydrolysis
GTP
GTPase is activated by the binding of GTP caused by guanine exchange factors. GTPase is inactivated by GTPase regulatory proteins. GTPase regulatory proteins inhibit GTPase in response to GTP hydrolysis
Most common G protein receptor
Rhodopsin family
Least common G protein receptor
metabatorpic glutamate
Kinase linked receptor
consists of dimers linked through dimerisation via ligand binding which use direct coupling to link intracellular to extracellular domain to induce the effector kinase proteins. Kinase autophosphorylates tyrosine residues on the catalyctic domain/ associated enzyme to activate itself following dimerisation triggered by ligand binding. regulate gene transcription and control cell growth. Structure consists of two transmembrane helix linked by ligand. EG,.
Recoetors from fastest to slowest
Ligand gated > G protein > Kinase > Nucelar
Intracellular receptor
They use DNA to connect the intracellular domain and extracellular domain to induce gene transcription. There are two types:
cytoplasmic- forms homodimer interactions and triggered by ligand binding, translocate to the nucleus. Ligands are typically endocrine
nuclear- forms heterdoimer interactions with
It is a monomeric structure with receptor domain for ligand seperate from the DNA binding domain
Absorption
Accumulation of drugs in compartment
First pass metabolism
Metabolising drugs in liver to make them more polar and easier to exccrete in the kdineys as urine
Vd
Volume distribution is the theoretical volume of a drug uniformly distirubted in the body to reach the same Cp( drug blood plasma conc).
High Vd
A high volume distribution is more likely if the drug can travel across compartments, such as morphine. This requires a higher volume because it has a greater pharmacological effect.
Low Vd
A low volume distribution is more liekly if the drug is limited to the plasma compartment, such as heparin. Therefore a lower volume is required because it has a greater pharmacological effect.
Treatment for NSAIDS
Misoprosol, prostaglandin mimetic which decreases gastric acid secretion