Serotonin Agonists and Antagonists PDF

Serotonin = 5-HT, [5-hydroxytryptamine] An indoleamine = has an indole ring structure Š‹••–”— –—”‡‹•ƒŽ•‘ˆ‘—†‹DzŠƒŽŽ— ‹‘‰‡‹ dz‘” psychedelic drugs 1. Biosynthesis and distribution a. from the amino acid L-tryptophan by hydroxylation of the indole ring followed by...

Serotonin = 5-HT, [5-hydroxytryptamine] An indoleamine = has an indole ring structure Š‹••–”— –—”‡‹•ƒŽ•‘ˆ‘—†‹DzŠƒŽŽ— ‹‘‰‡‹ dz‘” psychedelic drugs 1. Biosynthesis and distribution a. from the amino acid L-tryptophan by hydroxylation of the indole ring followed by decarboxylation of the amino acid  tryptophan 5-HTP hydroxylase decarboxylase tryptophan 5-HTP 5-HT Tissue Distribution ƒ enterochromaffin cells of the gastrointestinal tract (90% ) ƒ Platelets -10%  MAO SEROTONIN 5-hydroxyindoleacetaldehyde aldehyde dehydrogenase hydroxyindoleacetic acid (5-HIAA) Both are found in neurons and astroglia ƒ Outside the central nervous system: ƒ MAO-A is also found in the liver, gastrointestinal tract, and placenta. ƒ MAO-B is mostly found in blood platelets 1. Buspirone (Buspar) ƒ specific 5HT1a- receptor ƒ useful for the management of anxiety disorders ƒ effective nonbenzodiazepine anxiolytic ƒ Triptans are a family of tryptamine-based drugs used in migraines and cluster headaches. ƒ Sumatriptan (Imitrex] ƒ rizatriptan (Maxalt), ƒ Naratriptan (Amerge), ƒ Zolmitriptan (Zomig), 33.. Trazodone e ((Desyrel) Desyrel) ƒ metabolized to m- chlorophenylpiperazine, ƒ an activator activvato or o off 5HT1B and 5HT2 5H HT2 receptors recepto ors ƒ Anti- depressant agent 4. Cisapride (Propulsid) ƒ gastroprokinetic agent ƒ a drug g tha th that hat increases in ncreases motil motility ity in i the u upper uppe gastrointestinal er g gaastrointestin strointestin na l tract ƒ a newer 5-HT4 partial agonist ƒ used for irritable bowel syndrome with constipation 1. Fluoxetine Fluoxxetine ((Prozac). Prozac). ƒ antidepressant ƒ MOA: decreased serotonin seroto onin n uptake ake into neurons. upta ƒ SSRII (fluoxetin (fluoxetine ne = Prozac)) 2. Dexfenfluramine (Redux) X ANORECTIC DRUG ƒ causes serotonin release and reduces serotonin reuptake into nnerve erve terminals terminals. s. ƒ for the treatment trreatment of obesity obesity. y. ƒ Adverse eeffect: ffect: pulmonary hypertensio hypertension on 3. Sibutramine (Reductil) X ANORECTIC DRUG no longer available in the U.S. people taking sibutramine had an increased risk of cardiovascular events such as heart attack and stroke. Cyproheptadine (Periactin) Dz‡–”‘dz- Ondansetron, Granisetron (Kytril) Ketanserin Ketanserin (Sufrexal) Clozapine (Clozaril) Risperidone (Risperdal) ƒ blocks both 5HT1- and 5HT2-receptors ƒ is a first-generation antihistamine with additional anticholinergic, antiserotonergic, and local anesthetic properties. ƒ Used for gastric dumping  2. Ondansetron , Granisetron (Kytril) ƒ 5HT3-receptor antagonists ƒ highly ef effective ffective in treatin treating ng the nausea and vomiting associated with chemotherapy and radiation therapy. therapy. ƒ iintravenously ntravenously or orally orallly 4.. 4 Ketanserin Ketanseriin (Sufrexal) (Sufrexal) ƒ specific 5HT2-receptor antagonist ƒ investigational drug ƒ found to lower blood pressure in experimentally induced hypertension. 5. Antipsychotic Clozapine (Clozaril) ƒ specific 5HT2A- and 5HT2C Ȃ and dopamine receptor antagonist ƒ An atypical antipsychotic ƒ agranulocytosis. Risperidone (Risperdal) ƒ antagonist at 5HT2A-, 5HT2C-, and dopamine (D2)-receptors ƒ an atypical antipsychotic drug which is mainly used to treat schizophrenia dz ‡ PRACTICE Qs to follow. 10 5 minutes minute minutes es a End MAO-A A is is the amine oxidase primarily responsible responsiblle for for the meetabolism ooff N metabolism orepiinephhriine, S Norepinephrine, erottoniin, aand Serotonin, nd tyrami ine, tyramine, while w hile MMAO-B AO-B is the specific for the metab metabolism bolism of Dopamine. Which of the following agents is a selective reversible MMAO-A AO-A inhibitor inhhibitor whose adv advantage vantage is a llesser esser risk causing of ca hypertensive ausing hyper crisis rtensive crisi with is withh ttyramine yraminee foods? foods? Selegiline A. Se elegiliinee Nefazodone B. Nefazod done Moclobemide C. M oclobbemide Trazodone D. Trazod done Imipramine E. Im mipramine Which of the following drugs when given to patients will necessitate weekly WBC monitoring for the first 6 months of therapy and every 3 weeks thereafter due to its propensity to cause agranulocytosis? A. thioridazine B.Chlopromazine C. Loxapine D. Clozapine E. Molindone What is the primary mechanism of action of the drug Ondansetron and Granisetron? a.Partiaal agonist effect at the 5-HT1A receptor b.Antagonist effect at the 5-HT1B receptor c.Full agonist effect at the 5-HT22AA receptor d.Antagonist effect at the 5-HT3 receptor e.Partial agonist effect at the 5-HT4 receptor What is the clinical use of the drugs Ondansetron and Granisetron? a.Appetite suppressants b.Anti-emetic c.Treatment of acute migraine attack d.Migraine prophylaxis e.Motility enhancing agent What is the clinical use of the drugs that primarily stimulate the 5-HT1B and 5- HT1D receptors? a.Appetite suppressants b.Anti-emetic c.Treatment of acute migraine attack d.Migraine prophylaxis e.Motility enhancing agent What is Rasageline? A. A selective MAO-A inhibitor B. A selective MAO-B inhibitor C A COMT inhibitor D. A Dopamine-3 receptor Agonist E. A Dopamine-2 receptor agonist