Study Set Content:
Chemicals released from glands or cells that enter the bloodstream in order to travel round the body, activating all the receptors that recognize them. - not swiftly deactivated.
Hormones
a hormone released from the adrenal medulla in situations of stress or danger, and which prepares the body for physical exercise.
Epinephrine (Adrenaline)
diverse actions in the body
Steroids
activated by acetylcholine
Cholinergic receptors -
activated by epinephrine
Adrenergic receptors (α and β
- activated by dopamine
Dopaminergic receptors
Various receptors show(blank)for one chemical messenger over another because they have binding sites of different shape, structure and amino acid composition.
selectivity
Different receptor types are not evenly distributed around the
body
Heart has more β than α adrenergic receptors – this means that drugs that are selective for β- adrenergic receptors will act on the heart rather than on tissues that are rich in
α-adrenergic receptors.
Such selectivity is crucial in designing drugs with fewer
side effects
drugs that bind to the receptor binding site and mimic the natural messenger (affinity and intrinsic activity)
Agonist
drugs that bind to the receptor binding site, but do not activate the receptor (affinity)
Antagonist
Are usually caused when a drug binds to more than one type of receptor
side effects
Major goal in drug design which will be selective for (blank) of receptor as possible
one type
All membrane bound receptors belongs to one of the three following families:
a. Ligand-gated ion channels
b. G-protein – coupled proteins
c. Kinase-linked receptors
– protein complex that traverse the cell membrane and form a tunnel through it.
lon channels
allows the flow of ions across the cell membranes and there are specific ion channels for sodium, potassium and chloride ions.
lon channels
Without ion tunnels, (blank) could not cross the fatty cell membrane
ions
Normally closed and are only opened when signaled to do so (receptor comes in controlling whether the ion channel is
open or closed
closed receptor's binding site is unoccupied.
Resting state:
