Histamine, serotonin, depression Flashcards
Exam 3
What are the mediators in the autocoid group?
Histamine, serotonin, prostaglandins, leukotrienes
_____ is the mediator of allergic and inflammatory response
histamine
Histamine is released in response to what?
- Allergen binding to IgE on mast cells
- Displacement – morphine, tubucurarine
- Rupture of mast cells (mechanical)
Where are histamine H1 receptors located?
smooth muscle, endothelium, brain
Where are histamine H2 receptors located?
GI, cardiac muscle, mast cells, brain
Where are histamine H3 receptors located?
brain
Where are histamine H4 receptors located?
eosinophils, neutrophils, CD4 T cells
What are the 3 components of the triple response of allergy testing?
1- Wheal/welt development
2- flare/redness
3- Sensory nerve ending activation/itching
What is the physiologic antagonist of histamine?
Epinephrine
Differentiate between H1 antagonists, 1st vs 2nd gen
1st generation
- Sedative effects
- ANS blocking
- motion sickness, nausea
2nd generation
- Less sedation (↓ CNS distribution, doesn’t cross BBB)
What is the clinical use of H1 antagonists?
Prevent/treat symptoms of allergic response - Allergic rhinitis, urticaria
Why does morphine cause itching?
Histamine release
Histamine is released after __________ degranulation
mast cell
Which histamine receptors stimulate pain and itching?
H1 and H3
What histamine receptors are located in the stomach?
H2
Anti-muscarinic effects are more noted in the 1st generation or 2nd generation antihistamines?
1st generation (urinary retention and blurred vision)
Histamine effect on GI smooth muscle
contraction
Histamine effect on on CV system
vasodilation - decreases BP
reflex tachycardia
Histamine effect on on respiratory system
Bronchoconstriction
What are the 3 drugs that are 1st gen H1 antagonists?
Bendryl, Phenergan, Dramamine
What are the 3 drugs that are 2nd gen H1 antagonists?
Claritin, Allegra, Zyrtec
What class of drugs are OTC antacids?
H2 antagonists
Where is serotonin produced?
Raphe nuclei
Where is most of the serotonin stored in the body?
Gut - Enterochromaffin cells (90% of serotonin in body)
Serotonin effect on CV
- Contraction of vascular SM
- Exception: skeletal muscle, heart
- Platelet aggregation
Serotonin effect on GI
- Increases tone
- Facilitates peristalsis
- Overproduction - diarrhea
Serotonin effect on respiratory
- Facilitate ACh release - constriction
- Hyperventilation
Serotonin effect on nervous system
- Melatonin precursor
- Vomiting reflex
- Pain and itch (similar to histamine)
- Chemoreceptor reflex
- Bradycardia
- Hypotension
Which serotonin receptor is an ion channel?
5-HT3
- the other 6 are GPCRs
Which serotonin receptors are agonist targets?
1A, 1B, 1D
Which serotonin receptors are antagonist targets?
2A and 3
What are the 2 serotonin agonist drugs? Which receptors do they target? What do they treat?
- Buspirone
- 5-HT1A agonist (partial)
- Non-benzodiazapine anxiolytic - no drowsiness
- GAD, OCD - Sumatriptan
- 5-HT1D/1B agonist
- Migraine HA
What are the known components that contribute to migraines?
CGRP, Substance P, trigeminal nerves
What are the symptoms of migraines?
- Aura
- Severe HA
- N/V
- Photophobia
- Phonophobia
- Speech abnormalities
What are the 5 meds used for migraine treatment?
- Pain relief – ASA, NSAIDs, ASA+Caffeine, Opioids
- Triptans – 5-HTr Agonists
- Ergotamine – less effective than triptans
- Anti-nausea – chlorpromazine, ondansetron
- Glucocorticoids - prednisone
How do triptans treat migraines?
- Bind 5-HT1D/1B in cranial blood vessels
- Prevent dilation and stretching of pain endings
- Not prophylactic
What are the drugs used to prevent migraines?
- Beta-blockers, CCBs, ACEi
- Antidepressants – SSRIs, TCAs
- Anti-seizure – Valproate, Topiramate
- Botox
- MAbs - Aimovig (CGRP)
What are the 3 hyperthermic syndromes?
- Serotonin syndrome
- Neuroleptic malignant syndrome
- Malignant hyperthermia
What are the non-serotonin drugs used for weight loss?
- Liraglutide – GLP-1 agonist (diabetes)
- Orlistat – GI Lipase inhibitor
What drugs can cause serotonin syndrome?
Antidepressants (SSRIs, SNRIs, MAOIs), opioids, illicit drugs, St. John’s wort, ginseng
What is the treatment for serotonin syndrome?
Sedation (benzos), paralysis, intubation, and ventiliation
What drugs can cause neuroleptic malignant syndrome?
D2-blocking antipsychotics
How is neuroleptic malignant syndrome treated?
Parenteral Benadryl (diphenhydramine)
cooling, sedation (benzos)
What drugs can cause malignant hyperthermia?
Volatile anesthetics, sux
What is the treatment for malignant hyperthermia?
Dantrolene, cooling
What are the 3 drugs classified as serotonin antagonists? What receptors do they act at? What is their clinical use?
Phenoxybenzamine, Cyproheptadine
- 5-HT2
- Carcinoid tumors
- Cold induced urticaria
Ondansetron
- 5-HT3
- Prevent N/V for Surgery and CA chemotherapy
Dopamine is a _____ derivative
tyrosine
What are the dopamine receptors?
5 receptor types (D1–D5, all metabotropic)
What are the 3 major dopamine pathways?
- Nigrostriatal - Motor movement
- Mesolimbic - Reinforcement and Addiction
- Mesocortical - Working memory and planning
What are the 5 types of depression?
- Dysthymia
- Psychosis
- Postpartum
- Seasonal affective disorder (SAD)
- Bipolar disorder
What are the 4 types of anxiety?
- Generalized Anxiety Disorder (GAD)
- Obsessive-Compulsive Disorder (OCD)
- Post-Traumatic Stress Disorder (PTSD)
- Social Phobia
What are the 4 major classes of antidepressants?
- Selective serotonin reuptake inhibitors (SSRIs)
- Selective serotonin-NE reuptake inhibitors (SNRIs)
- Tricyclic antidepressants (TCAs)
- Monoamine oxidase inhibitors (MAOIs)
All antidepressant’s increase _______ NT levels within the synapse
monoamine
SSRIs inhibit ______
SERT
SNRIs inhibit ____
SERT and NET
TCAs inhibit _____
Inhibit SERT, NET, some anticholinergic effects
SSRI drugs
Fluoxetine (Prozac)
Sertraline (Zoloft)
SNRI drugs
Desvenlafaxine (Pristique)
Duloxetine (Cymbalta)
- More severe depression and pain disorders
TCA drug
Amitriptyline (Elavil)
MAOIs are used to treat _______ but are rarely used due to _____
Refractory depression, unresponsive to others
Lethal drug interactions
What are the adverse effects of antidepressants?
Suicidal, drug interactions, N/V/D, Sexual dysfunction
Serotonin is a derivative of _______
tryptophan
What are the serotonin drugs that are no longer used for weight loss?
(Dex)Fenfluramine - 5-HT2 agonist
Lorcaserin – 5-HT2C agonist
What are the alternative therapies for anxiety and depression?
St. John’s Wort, Talk therapy, Electroconvulsive
What are NDRIs? What are the drugs given in class and what do they treat?
- Buproprion (Wellbutrin), Solriamfetol (Sunosi)
- Inhibits NE and DA reuptake
- Depression, ADHD, GAD, daytime sleepiness
What are the antipsychotics? What are their uses?
Major depression (with SSRIs)
Aripiprazole (Abilify)
Amisulpride - Schizophrenia
- D2 receptor antagonist
If your patient has a history of Prinzmetal angina then they should not take ______ for their migraines
Sumatriptan