Receptors and Drug Action Receptors: •Specific areas of cell membranes (proteins, glycoproteins)* •When bound to ligand, positive or negative biological responce Ligand cellmembrane with receptor Biological responce * Few ex. of free receptors in cytoplasma Cell Nucleus Cell membrane Organelles Cytoplasma Extracellular fluid Drugs that do not act on receptors: Antacida: CaCO 3 + HCl Diuretica (osmotic) Akylating agents (cancer) Cl N Cl N Cl Nu N Cl Nu Drugs that do act on receptors: N O O O H ca. 5Å Acetylcholin (Neurotransmittor) N O O H 2 N Carbacholin N N Me H O O Acetylcholin Agonists Pilocarpine Acetylcholin Antagonists N O O OH Atropin O O N OH Cyclopentolat O O O R R' HN N O O O O O R R' HN N N N O O NH 2 O N N NH 2 O h! Psoralenes Agonist: Binds to (have affinity for) receptor Binding leads to biolog. responce (Agonists have intrinsic activity / efficacy) Antagonist: Affinity for receptor No intrinsic activity
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Receptors and Drug Action
Receptors:
•Specific areas of cell membranes (proteins, glycoproteins)*
•When bound to ligand, positive or negative biological responce
Ligand
cellmembrane with receptor
Biological responce
* Few ex. of free receptors in cytoplasma
Cell Nucleus
Cell membrane
Organelles
Cytoplasma
Extracellular fluid
Drugs that do not act on receptors:
Antacida: CaCO3 + HCl
Diuretica (osmotic)
Akylating agents (cancer)
ClN
ClN
Cl
Nu
N
Cl
Nu
Drugs that do act on receptors:
NO
O
OH
ca. 5Å
Acetylcholin (Neurotransmittor)
NO
O
H2N
Carbacholin
N
N
Me
H
OO
Acetylcholin Agonists
Pilocarpine
Acetylcholin Antagonists
N
O
O
OH
Atropin
O
O
N
OH
Cyclopentolat
OO O
R
R'
HN
N
O
O
OO O
R
R'
HN
N
NNO
O NH2
ONN
NH2
O
h!
Psoralenes
Agonist:
Binds to (have affinity for) receptor
Binding leads to biolog. responce
(Agonists have intrinsic activity / efficacy)
Antagonist:
Affinity for receptor
No intrinsic activity
Binding of ligand to receptor
•Covalent bond
•Ionic bond
•Hydrogen bond
•Hydrophobic interaction
Covalent bond
strong; 50-150 kcal/mol,
Normally irreversible bonding
ex. Acetylcholine esterase inhibitors
Effector celleSynapse
reseptor
AcCh
Nerve potensial
AcCh
AcCh (exess)
AcCh-esterase
Ch
ChCh-acetyl-transferase
AcCh
Nerve cell
NO
O
Acetylkolin(AcCh)
Acetylkolin-esterase
Kolin Acyltransferase
NOH
Kolin(Ch)
Reversible inhibitors
OH OO
OH O
OH
NO
O
NHO
k3(AcCh)
AcCh
Inhibitor
Neostigmin Pyridostigmin
Myastenia gravis (weak muscles, reduced sensitivity to Acetylcholine)O