introduction to pharmacology Flashcards
what is the definition for drugs
-a chemical substance of a known structure, other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect
definition for pharmacology
the study of mechanisms by which drugs affect the function of living systems (interaction of drugs and receptors)
what is the importance of bioassays
-assays in which the concentration or potency of a substance is measured by the biological response it produces
-measure the pharmacological activity of new or chemically undefined substances
-investigate the function of endogenous mediators
-measure drug toxicity and unwanted effects
what are the fundamental principles of pharmacology
-drug action must be explicable terms of conventional chemical interactions between drugs and tissues (must be able to explain it)
-drug molecules must be ‘bound’ to particular constituents of cells and tissues in order to produce an effect (out or inside of cells but normally out because its easier)
-drugs molecules must exert some chemical influence on one or more constituents of cells in order to produce a pharmacological response
what are the 4 types of proteins normally targeted by drugs
-enzymes
-transporters
-ion Chanels
-receptors
ligand definition
-any molecule that binds to the receptor, it may be an agonist or an antagonist
definition for agonist
drugs or chemical mediators that bind to a receptor producing a response
definition of an antagonist
-drugs that prevent or inhibit the response of an agonist
-may bind to the receptor but don’t elicit a response
-majority of clinically useful drugs
-competitive antagonism- binding to receptors that agonist would usually bind to
what do you normally find in receptor families
-‘subtypes’ with distinct subunit compositions and pharmacology
-e.g. nAChR which is important in the neuromuscular junction and can target a specific type of nAChR
-can block the receptors in the brain to stop people being addicted to nicotine
what are side effects caused by drugs lacking specificity
-many receptors found in more than one organ
-drugs will bind to receptors wherever they are located
-this can lead to side effects
- a common example is opioid receptors: morphine blocks signals which are going to the brain for pain therefore preventing pain, but they’re really addictive as there are lots of opioid receptors in the brain associated with rewards, alongside awful gut effects
what is therapeutic manipulation of contact-dependent signalling
-CAR T immunotherapy uses contact-dependent signalling to kill cancer cells: relatively new therapy, cancer treatment isn’t very specific
-CAR= chimeric antigen receptor, ‘engineered’ receptor designed to recognise cancer cell e.g. T cells with antigens which only recognise cancer cells
how can paracrine signalling be affected by drugs acting on receptors
-paracrine signalling is chemical mediators related to neighbouring cells
-mast cells located under the skin detect allergens
-activated mast cells secrete mediators e.g. histamine which act locally to produce vasodilation (blood vessels widen) and activate neurons involved in itch
-many over the counter allergy medicines contains drugs which block receptors for histamine
how is paracrine signalling affected by drugs acting on enzymes
-eicosanoids such as prostaglandins are lipids and derived paracrine mediators that cause inflammation
-drugs such as paracetamol can target enzymes which synthesise the mediators
-some drugs work by preventing the breakdown of signalling molecules
nitric oxide causes relaxation of smooth muscle cells causes relaxation of smooth muscle cells and vasodilation
-viagra inhibits the enzymes responsible for the breakdown of cGMP, prolonging no action
how can drugs target ion channels involved in regulating neurotransmission
-drugs can act block voltage-gated Na+ channels
-this prevents action potential generation
-uses local anaesthetics e.g. lidocaine
drugs of abuse can target transporters involved in neurotransmission
-drugs can target transporters found on the cell membrane and vesicle membrane
-e.g. amphetamines indirectly increases noradrenaline releases by displacing it from its vesicles
