Neurotransmitters Flashcards
What are the 2 “fast response” type of receptors?
Ion Receptors, G protein coupled receptors
What are the 2 “slow response” type of receptors?
Enzyme linked transmembrane receptors, Intracellular receptors
What are examples of ligand gated ion receptors?
Nicotinic receptors, NMDA, GABA
What kind of receptor do local anesthetics work on?
Voltage-sensItive ion channel
What type of receptor is the most abundant in the body?
G-protein coupled receptors
How does a G-protein coupled receptor work and what are some examples?
The receptor activates or inhibits an enzyme, it uses a second messenger system to work at an effector protein to target the ion channel or a target receptor. Ex: hormones, catecholamines, opioids, anticholinergics, antihistamines
In both the PNS and SNS, you will see _____ interact with a ______ receptor
acetylcholine, nicotinic
What two substances come together to make acetylcholine? What substance is located within the synapse?
AcetylCoA and Choline, choline acetyltransferase
Acetylcholine is stored in ____ until the neuron fires
vesicles
After traveling to the post synaptic membrane, what does acetylcholine break down in to? What is the substance that breaks it down?
Choline and acetate, acetylcholinesterase
What type of receptors are nicotinic receptors? Where are they located?
Ligand gated, neuromuscular junction, autonomic ganglia, and CNS
What are 3 agonists of nicotinic receptors?
Acetylcholine, succinylcholine, nicotine
What type of receptor are muscarinic receptors?
G-protein coupled
What are muscarinic receptors stimulated by? Blocked by?
Stimulated: acetylcholine, muscarine. Blocked: atropine, scopolamine, pilocarpine.
What does stimulation of muscarinic receptors do?
Salivary and sweat gland secretion, pupillary constriction, increased GI peristalsis, slows SA and AV nodes. (parasympathetic effects)
Where is dopamine synthesized?
CNS neurons
Where is Epi and Norepi synthesized?
second-order neurons of the SNS in the adrenal medulla. Norepi also in CNS neurons
How many subgroups are there of muscarinic receptors?
5, M1-M5
What are the two receptors classes of dopamine?
D1-like, D2-like
What subclasses are in D1-like dopamine class? What do they do?
D1, D5. Increase cAMP (by a second messenger system)
What are the subclasses in the D2-like dopamine class? What do they do?
D2, D3, D4, decrease cAMP
What are the central functions of dopamine?
memory, problem solving, reward-pleasure, inhibition of prolactin secretion, fine control of movement, nausea and vomiting (chemoreceptor trigger zone)
What are the peripheral functions of dopamine?
Coronary and renal vasodilation
What are agonists of dopamine receptors and what are their side effects?
Dopamine, L-dopa. Side effects: Euphoria, psychosis, orthostatic hypotension, nausea
What are antagonists of dopamine receptors and what are their side effects?
Haloperidol, other antipsychotics, antiemetics (metaclopramide, droperidol) Side effects: parkinsonism (tremors, extrapyramidal reactions), hyperprolactinemia
What are the two classes of adrenergic receptors?
alpha and beta
How many classes does each have? Alpha: Beta:
Alpha: 2, Beta: 3
What is histamine synthesized from? Which 3 locations?
histadine. CNS, Immune cells (basophils & mast cells), GI tract (mast cells in stomach)
How many types of receptors does Histamine have?
3, H1, H2, H3
Where are H1 receptors located and what do they do? What are examples of antagonists?
located on vascular smooth muscle and in CNS
Dilate vascular smooth muscle, constrict bronchial smooth muscle (think allergic rxn)
Antagonists: diphenhydramine, loratadine
Where are H2 receptors located and what do they do? What are examples of antagonists?
Located in stomach, they increase acid secretion. Antagonists: famotidine
Where are H3 receptors located and what do they do?
presynaptic reduction in further histamine release
Serotonin is found in the ____ nucleus in the brainstem and projects to other regions of the brain to regulate ____, ____, and ____.
Raphe
mood, cognition, sleep
____ is the only serotonin receptor that is ligand gated. It causes _____.
5HT3, nausea
What medication is a serotonin antagonist?
ondansetron (antiemetic)
What is Substance P?
An amino peptide produced from pain in the CNS and PNS
What are substance P receptors?
Neurokinin receptors, NK1, NK2, NK3
Substance P blocked in the ___ and ____ will reduce nausea through the ______.
gut and the CNS, CTZ (chemoreceptor trigger zone)
What are the 6 neurotransmitters associated with PONV? (technically one is not a NT)
Dopamine, Serotonin, Acetylcholine, Histamine, Substance P, Opioids.
What is the primary brain excitatory neurotransmitter?
Glutamate
What is the primary spinal cord excitatory neurotransmitter?
Aspartate
Which neurotransmitter is the most prominent in the brain?
Glutamate
T or F: Glutamate is charged so it does not cross the blood-brain barrier
True
All glutamate is synthesized from _____, which crosses the blood brain barrier.
Glutamine
What is a glutamate receptors important to anesthesia?
NMDA
NMDA requires co-activation with ____ and ____
glutamate and glycine
What are 2 NMDA antagonists?
Nitrous and Ketamine
What is the primary inhibitory neurotransmitter in the brain? (2nd most abundant)
GABA
What is the primary inhibitory neurotransmitter in the spinal cord?
Glycine
Where is GABA synthesized? What is it converted from?
Pre-synaptic neuron, converted from Glutamine (goes from excitatory NT to an inhibitory NT)
What is allosteric regulation?
Binding of a drug or chemical at a site DIFFERENT that increases the affinity for GABA to bind and react.
What are some positive allosteric modulators?
Propofol, Benzos, Sterioids, Barbituates
What is a negative allosteric modulator?
Flumazenil
