Serotonin and Related Drugs Flashcards

Vocabulary flashcards for reviewing Serotonin lecture notes.

Serotonin

Also known as 5-hydroxytryptamine (5HT); a medically important neurotransmitter with diverse biological functions.

Tryptophan Hydroxylase

Enzyme that converts Tryptophan to 5-Hydroxytryptophan in the synthesis of serotonin.

Aromatic Amino Acid Decarboxylase

Enzyme that converts 5-Hydroxytryptophan to 5-hydroxytryptamine in the synthesis of serotonin.

Monoamine Oxidase (MAO)

Enzyme involved in the metabolism of N-acetyl serotonin to 5-Hydroxy indole acetic acid (5HIAA).

Aldehyde Dehydrogenase

Enzyme involved in the metabolism of N-acetyl serotonin to 5-Hydroxy indole acetic acid (5HIAA).

Melatonin

Hormone produced from N-acetyl serotonin in the pineal gland, involved in setting circadian rhythms.

5-Hydroxyindole Acetic Acid (5HIAA)

Metabolite of serotonin; elevated levels indicate hypersecretion of serotonin.

Enterochromaffin Cells

Cells in the gastrointestinal tract (GIT) that synthesize and store serotonin.

Myenteric Plexus

A network of nerves in the GIT, some of which are serotonergic, containing serotonin.

Na+ Dependent Carrier

Transporter in platelets that mediates the uptake of serotonin from the blood.

Tryptaminergic Neurons

Neurons in the CNS that synthesize serotonin de novo.

5HT1 Receptors

A family of G-coupled serotonin receptors that decrease cAMP levels by inhibiting adenylate cyclase.

Adenylate Cyclase

Enzyme inhibited by 5HT1 receptors, leading to decreased cAMP levels.

Receptor Operated K+ Channels

Channels activated by 5HT1A receptors, affecting ion conduction in the brain.

Voltage Gated Ca2+ Channels

Channels inhibited by 5HT1A receptors, affecting ion conduction in the brain.

Substantia Nigra

Brain region where 5HT1D receptors are expressed and may regulate dopamine release.

Basal Ganglia

Brain region where 5HT1D receptors are expressed and may regulate dopamine release.

Pial and Coronary Vessels

Vessels on which 5HT1D receptors are found, causing vasoconstriction.

Sumatriptan

5HT1D agonist used for migraine treatment that may cause coronary vasoconstriction as a side effect.

Coronary Atherosclerosis

Condition where reduction in luminal radius due to vasoconstriction may result in coronary ischemia.

Autoreceptors

Receptors that regulate the release of neurotransmitters; 5HT1A and 5HT1D act as inhibitory autoreceptors.

Somatodendritic Autoreceptors

Inhibitory autoreceptors (5HT1A) located on serotonergic nerves in the raphe nucleus of the brainstem.

Presynaptic Autoreceptors

Inhibitory autoreceptors (5HT1D) located on presynaptic terminals of serotonergic neurons.

Raphe Nuclei

Brainstem nuclei where serotonergic cell bodies and autoreceptors are located.

Neuromodulator

A substance that diffuses out of the synaptic cleft to affect nearby nerves, such as serotonin.

Phospholipase C

Enzyme activated by 5HT2 receptors, involved in intracellular signaling.

5HT2A Receptors

Serotonin receptors found throughout the brain, on platelets, and on smooth muscle cells, involved in platelet aggregation and smooth muscle contraction.

5HT2B Receptors

Serotonin receptors found in the stomach fundus, mediating contraction of smooth muscle.

5HT2C Receptors

Serotonin receptors found in the choroid plexus, with unknown function.

Ligand Gated Ion Channel

Type of receptor that 5HT3 is, composed of 4 transmembrane spanning regions.

Neuroexcitatory

Describes the action of 5HT3 receptors on peripheral sensory (afferent) nerves.

Vagal and Splanchnic Afferents

Peripheral sensory nerves where 5HT3 receptors are located.

Nucleus Tractus Solitaries

Area within the brainstem, where 5HT3 receptors can be found.

Area Postrema

Brain region where 5HT3 receptors are located; plays a role in emesis.

Myenteric Plexus

Location in the gut where 5HT4 receptors are found.

Secretory Cells

Cells where 5HT4 receptors are found in the gut, promoting secretion.

Peristaltic Reflex

Physiological process facilitated by 5HT4 receptors in the gut.

Carcinoid Syndrome

Condition due to overproduction of serotonin by a tumor of enterochromaffin cells.

Fenclanine

Serotonin synthesis inhibitor used to treat carcinoid tumors.

Cyproheptadine

Drug that blocks 5HT receptors (as well as H1 receptors), used in the treatment of carcinoid syndrome.

Hemostasis

The process of blood clotting; serotonin plays a role via platelet aggregation.

Dense Core Granules

Structures in platelets where serotonin is stored in high concentration.

Endothelium

The inner lining of blood vessels; intact endothelium produces anti-aggregatory factors.

EDRF (Endothelium-Derived Relaxing Factor)

Anti-aggregatory factor, such as nitric oxide (NO), produced by intact endothelium.

Thromboxane A2

Factor released from platelets upon endothelial damage, promoting platelet aggregation.

Vasoconstriction

The constriction of blood vessels, caused by serotonin acting on 5HT2A receptors on vascular smooth muscle.

Vasodilatation

The dilation of blood vessels, caused by serotonin acting on 5HT1 receptors and releasing EDRF.

Atherosclerosis

Disease in whose pathogenesis serotonin may have a role.

Coronary Vasospasm

Condition where platelets release seratonin abnormally.

Raynaud's Syndrome

Condition involving constriction of vessels in hands and periphery, leading to cold extremities; serotonin may play a role.

Bezold-Jarisch Reflex

Reflex consisting of bradycardia and hypotension, resulting from direct stimulation of vagal nerve endings by serotonin (5HT3 mediated).

Histamine

Chemical whose effects are amplified by serotonin.

SA Node

Part of the heart where serotonin increases the rate, thus increasing the heart rate (5HT4 mediated).

Peristalsis

Process in the gut increased my 5HT4 which increases the transit time.

Emesis

Vomiting; may be stimulated by serotonin acting on 5HT3 receptors on afferent nerves in the gut.

Blood Brain Barrier

Structure that prevents serotonin from the periphery from entering the CNS.

P-chlorophenylalanine (Fenclonine)

Drug that inhibits the synthesis of serotonin.

Reserpine

Drug that inhibits the uptake of serotonin into storage vesicles and promotes direct release of serotonin from the nerve.

Iproniazid

Drug that inhibits the enzyme MAO, which is used to degrade serotonin.

8-OH-DPAT

Drug that modulates serotonin release via the 5HT1D receptor (agonist), inhibiting exocytosis of vesicles storing serotonin.

Fluoxetine

Drug that prevents the reuptake of serotonin, thus prolonging its action.

NA releasing neurons

Neurons whose activity is increased by a primary neuronal disturbance in the theories of migraines.

Nociceptive Nerve Terminals

Nerve Terminals sensitized by prostglandins and bradykinin during perivascular inflammation.

Sumatriptan

Drug that acts on the 5HT1D inhibitory autoreceptor to prevent the release of serotonin from serotonergic nerves.

Ergotamine

Drug that causes vasoconstriction of the cerebral vasculature.

Chemoreceptor Trigger Zone (CTZ)

Brain area with 5-HT3, NK1, and dopamine receptors that stimulates the vomiting center.

Medullary Emetic Center

Area in the brain the all pathways involved in emesis finally reach.

Vomiting Center (VC)

Structure with 5-HT3 and NK1 receptors.

Diphenhydramine

Antagonist of H1 useful in the treatement of emesis.

Ondansetron

Antagonist of 5-HT3 useful in the treatement of emesis.

Metoclopromide

Antagonist of D2 useful in the treatement of emesis.

Scopolamine

Antagonist of M useful in the treatement of emesis.

Kinins

Local mediators of pain and inflammation; a family of small peptide molecules.

Bradykinin

A type of kinin; a small peptide molecule that is a local mediator of pain and inflammation.

Kallidin

A type of kinin; a small peptide molecule that is a local mediator of pain and inflammation.

Hageman Factor

Clotting factor activated by tissue damage, leading to kinin production

Plasma Prekallikrein

Inactive precursor converted to plasma kallikrein by Hageman factor.

Kallikreins

Enzymes that break down kininogens (precursors of kinins).

Kininogens

Precursors of kinins; liver-derived alpha2 globulins.

Amino Peptidases

Enzymes that metabolize kallidin and bradykinin.

Carboxypeptidases

Enzymes that metabolize kinins, including kininase 1 and kininase II (ACE).

Kininase 1

Carboxypeptidase that inactivates des Arg9 Bradykinin.

Kininase II (ACE)

Carboxypeptidase that inactivates Bradykinin.

Des Arg9 Bradykinin

Kinin that mediates vasoconstriction by acting on the B1 receptor.

Icatibant

Drug that acts on B2

Aprotinin

Drug acting to inhibit kallikreins & treat angioedema.

ACE Inhibitors

Drugs that increase amount of bradykinin (dilator) reducing vasoconstriction.

Mycotoxins

Produced by several species of fungi in the genus Claviceps.

Claviceps

Genus of fungi that produces mycotoxins.

Clavines

Main groups of classification of Ergot Alkaloids.

Lysergic Acid

Main groups of classification of Ergot Alkaloids.

Lysergic Acid Amides

Main groups of classification of Ergot Alkaloids.

Ergopeptide

Main groups of classification of Ergot Alkaloids.

Ergotism

Disease caused by ergot poisoning.

Ergotamine

Building blocks of the psychoactive drug called Lysergic acid diethylamide (LSD).

Ergometrine

E.g of Ergot Alkaloids.

Cafergot

E.g of Ergot Alkaloids ( Ergotamine + Caffeine).

Oxytocin

Uterine muscle stimulants (Post. Pituitary hormone).

Ergometrine, Ergonovine

Uterine muscle stimulants.

Methyl Ergometrine

Uterine Muscle Stimulant.