Pharmacology Flashcards
G-Protein α-Subunit Gs β-adrenoceptors; Histamine H2 receptors; Serotonin 5-HT4 receptors; Glucagon
↑adenylyl cyclase activity leading to ↑ levels of cyclic AMP
Gi1, Gi2,Gi3 α2-adrenoceptors; Muscarinic cholinergic M2 and M4; Serotonin 5-HT1; Opioids, cannbinoid
↓ adenylyl cyclase activity leading to ↓ levels of cyclic AMP; Open potassium channels
Gq Muscarinic cholinergic M1, M3 and M5; Serotonin 5-HT2; α1-adrenoceptors;
↑ phospholipase C activity leading to ↑ levels of IP3 and diacylglycerol that increase intracellular Ca2+
Target for GPCRs
Adenylyl cyclase, the enz responsible for Camp phospholipase C, the enzyme responsible for inositol phosphate and diacylglycerol (DAG) formation ion channels, particularly calcium and potassium channels
Therapeutic Uses of Direct-Acting Cholinergic Receptor Agonists Bethanechol
Postoperative ileus
Congenital megacolon
Urinary retention
Therapeutic Uses of Direct-Acting Cholinergic Receptor Agonists
Pilocarpine, Carbachol
Glaucoma
Edrophonium (Tensilon®)
, Tacrine (Cognex®),
Donepezil (Aricept®)
Galantamine (Reminyl®)
Indirect Acting Cholinomimetic Drugs:
Inhibitors of Acetylcholinesterase
Competitive Inhibitors
Reversible
Compete for ACh binding at the anionic site
Contains no ester linkage so that it is not hydrolyzed
Inhibition is rapidly reversible (increase Ach conc. will reverse their effect) DOA is not very long Tacrine discontinued due liver damage
Physostigmine,Rivastigmine (cross BBB)
Pyridostigmine, Neostigmine, (NOT CORSS BBB)
and Carbaryl, Propoxur and Aldicarb
Carbamate Inhibitors (garden products)
Reversible
They interact with 2 sites of the enzyme, the anionic site and they actually add carbamyl group to it.
Carbamyl ester linkage hydrolyzed to carbamylate enzyme Carbamyl moiety is slowly released - leads to long-lasting but reversible inhibition
Physostigmine and Rivastigmine are CNS permeable and used in treating Alzheimer’s disease
DFP (Isoflurophate); Echothiophate, (The only one therapeutically useful) Parathion, Tabun (GA), Sarin (GB), Soman (GF), VX (10x more potent than G-series)
Irreversible Inhibitors Used as insecticides and nerve gases Good CNS penetration (highly lipid soluble) Covalently phosphorylate the esteratic site of the enzyme (They phosphrylate that ser and the phosphrylation takes long time, good fortune) Phosphorylation is generally irreversible and enzyme must either be resynthesized or chemically reactivated by pralidoxime (2-PAM
Parathion,
Indirect Acting Cholinomimetic Drugs: Inhibitors of Acetylcholinesterase Irreversible Inhibitors Used as insecticides and nerve gases Good CNS penetration (highly lipid soluble) Covalently phosphorylate the esteratic site of the enzyme (They phosphrylate that ser and the phosphrylation takes long time, good fortune) Phosphorylation is generally irreversible and enzyme must either be resynthesized or chemically reactivated by pralidoxime (2-PAM
Tabun (GA)
Indirect Acting Cholinomimetic Drugs: Inhibitors of Acetylcholinesterase Irreversible Inhibitors Used as insecticides and nerve gases Good CNS penetration (highly lipid soluble) Covalently phosphorylate the esteratic site of the enzyme (They phosphrylate that ser and the phosphrylation takes long time, good fortune) Phosphorylation is generally irreversible and enzyme must either be resynthesized or chemically reactivated by pralidoxime (2-PAM
Sarin (GB),
Indirect Acting Cholinomimetic Drugs: Inhibitors of Acetylcholinesterase Irreversible Inhibitors Used as insecticides and nerve gases Good CNS penetration (highly lipid soluble) Covalently phosphorylate the esteratic site of the enzyme (They phosphrylate that ser and the phosphrylation takes long time, good fortune) Phosphorylation is generally irreversible and enzyme must either be resynthesized or chemically reactivated by pralidoxime (2-PAM
Soman (GF)
Indirect Acting Cholinomimetic Drugs: Inhibitors of Acetylcholinesterase Irreversible Inhibitors Used as insecticides and nerve gases Good CNS penetration (highly lipid soluble) Covalently phosphorylate the esteratic site of the enzyme (They phosphrylate that ser and the phosphrylation takes long time, good fortune) Phosphorylation is generally irreversible and enzyme must either be resynthesized or chemically reactivated by pralidoxime (2-PAM
VX (10x more potent than G-series)
Indirect Acting Cholinomimetic Drugs: Inhibitors of Acetylcholinesterase Irreversible Inhibitors Used as insecticides and nerve gases Good CNS penetration (highly lipid soluble) Covalently phosphorylate the esteratic site of the enzyme (They phosphrylate that ser and the phosphrylation takes long time, good fortune) Phosphorylation is generally irreversible and enzyme must either be resynthesized or chemically reactivated by pralidoxime (2-PAM
Carbaryl
Carbamate Inhibitors (garden products) Reversible They interact with 2 sites of the enzyme, the anionic site and they actually add carbamyl group to it. Carbamyl ester linkage hydrolyzed to carbamylate enzyme Carbamyl moiety is slowly released - leads to long-lasting but reversible inhibition Physostigmine and Rivastigmine are CNS permeable and used in treating Alzheimer’s disease
Propoxur
Carbamate Inhibitors (garden products) Reversible They interact with 2 sites of the enzyme, the anionic site and they actually add carbamyl group to it. Carbamyl ester linkage hydrolyzed to carbamylate enzyme Carbamyl moiety is slowly released - leads to long-lasting but reversible inhibition Physostigmine and Rivastigmine are CNS permeable and used in treating Alzheimer’s disease
Aldicarb
Carbamate Inhibitors (garden products) Reversible They interact with 2 sites of the enzyme, the anionic site and they actually add carbamyl group to it. Carbamyl ester linkage hydrolyzed to carbamylate enzyme Carbamyl moiety is slowly released - leads to long-lasting but reversible inhibition Physostigmine and Rivastigmine are CNS permeable and used in treating Alzheimer’s disease
Organ System Effects of Cholinesterase Inhibition Cardiovascular
Bradycardia Decreased Cardiac Output (CO) Hypotension (modest except in toxic doses
Organ System Effects of Cholinesterase Inhibition Respiratory System
Bronchoconstriction Increased secretion (copious) Paralysis of diaphragm
Organ System Effects of Cholinesterase Inhibition GI Tract
Increased tone Increased motility Increased secretions
Organ System Effects of Cholinesterase Inhibition Skin
Increased sweating
Organ System Effects of Cholinesterase Inhibition Eye
Miosis Near accommodation
Organ System Effects of Cholinesterase Inhibition Central Nervous System
Tremor Anxiety Confusion Convulsions Coma
Therapeutic Uses of Cholinesterase Inhibitors
Glaucoma Postoperative ileus, congenital megacolon, urinary retention Diagnosis and Treatment of Myasthenia Gravis Surmounting effects of competitive neuromuscular blocking agents Treatment of Alzheimer’s disease (increasing adverse cardiovascular events!!!) Treatment of Atropine poisoning (and al types of anticholinergic poisoning)
Diagnosis and Treatment of Myasthenia Gravis
Therapeutic Uses of Cholinesterase Inhibitors
Postoperative ileus, congenital megacolon, urinary retention
Therapeutic Uses of Cholinesterase Inhibitors
Glaucoma
Therapeutic Uses of Cholinesterase Inhibitors
Surmounting effects of competitive neuromuscular blocking agents
Therapeutic Uses of Cholinesterase Inhibitors
Treatment of Alzheimer’s disease (increasing adverse cardiovascular events!!!)
Therapeutic Uses of Cholinesterase Inhibitors
Treatment of Atropine poisoning (and al types of anticholinergic poisoning)
Therapeutic Uses of Cholinesterase Inhibitors