Neurotransmitters Flashcards
What are the major neurotransmitters?
- Acetylcholine
- Amino Acids
- Glutamate
- GABA
- Glycine
- Amino acid derived
- Serotonin
- Catecholamines
- norepinephrine
- dopamine
______ _____ Neurons use ACh as a modulator of motor coordination.
Basal Ganglia Neurons use ACh as a modulator of motor coordination
Basal Nucleus of Meynert neurons in basal forebrain synthesize ____ (these axons project widely in the cortex facilitating memory).
Basal Nucleus of Meynert neurons in basal forebrain synthesize ACh (these axons project widely in the cortex facilitating memory).
(It has been noted that the Nucleus Basalis of Meynert degenerates in Alzheimer’s disease resulting in a loss of ACh innervation of the neocortex. Many therapeutic interventions have targeted enhancing cholinergic activity in the CNS, but with limited success.)
_____ is the major excitatory neurotransmitter in the CNS.
Glutamate is the major excitatory neurotransmitter in the CNS.
Glutamate is often implicated in “_______” in which neurons under stress die when overly excited.
Glutamate is often implicated in “excitotoxicity” in which neurons under stress die when overly excited.
Where in the body does glutamate act? What is its mechanism of action?
Acts everywhere: Spinal cord, brain stem, cerebellum, hippocampus, cerebral cortex
Excitation of cognitive, motor and sensory function
____ is the major inhibitory neurotransmitter in the CNS.
GABA is the major inhibitory neurotransmitter in the CNS.
Where is GABA found in the body? What is its mechanism of action?
Found predominantly in interneurons - located throughout the CNS
Sedation & muscle relaxation, cardiovascular and respiratory function, spinal reflexes, pain perception
_______ bind to the GABA receptor complex and enhance its inhibitory actions on neural activiy.
Benzodiezopines bind to the GABA receptor complex and enhance its inhibitory actions on neural activiy.
Benzodiezopines bind to the ____ receptor complex and enhance its inhibitory actions on neural activiy.
Benzodiezopines bind to the GABA receptor complex and enhance its inhibitory actions on neural activiy.
Glycine is a(n) ______ neurotransmitter in the CNS.
inhibitory
Where does glycine act in the body?
Everywhere - spinal cord interneurons
Where is serotonin produced? What does it act on/control?
Produced in:
- Raphe nuclei in the brain stem project axons to all CNS regions
- Pineal Gland
Controls limbic function and sleep (sleep & arousal, pain perception, food intake, emotions, mood, temperature)
Serotonin neurotransmission is enhanced by drugs which inhibit reuptake of serotonin into the ______ neuron (SSRIs=Selective Serotonin Reuptake Inhibitors).
Serotonin neurotransmission is enhanced by drugs which inhibit reuptake of serotonin into the presynaptic neuron (SSRIs=Selective Serotonin Reuptake Inhibitors).
Endogenous examples of catecholamines:
Dopamine
Norepinephrine
Epinephrine
Where does the locus ceruleus project to?
Much of the cortex mediating arousal, attention, and anxiety
List 3 important catecholamines and 1 important synthetic enzyme:
Dopamine
Norepinephrine
Epinephrine
Tyrosine hydroxylase
_____ neurons synthesize dopamine and project axons to the ____.
Substantia nigra neurons synthesize dopamine and project axons to the basal ganglia.
Substantia nigra neurons synthesize _____ and project axons to the basal ganglia.
dopamine
Depletions in dopamine are connected to _____ (disease) and elevations in dopamine are connected to ____ (disease).
Depletions in dopamine are connected to Parkinson’s (disease) and elevations in dopamine are connected to Schizophrenia (disease).
Ionotropic channel characteristics:
Receptor is also an ion channel
Metabotropic channel characteristics:
Receptor activation triggers second messenger pathways:
Excitatory ionotropic receptors include those for: (4)
Glutamate
Acetylcholine
5-HT (serotonin)
ATP
Excitatory ionotropic receptors are ____ selective, whereas inhibitory ionotropic receptors are ___ selective
Excitatory ionotropic receptors are cation selective, whereas inhibitory ionotropic receptors are anion selective
Inhibitory ionotropic receptors include (2):
GABA
Glycine
Describe acetylcholine receptors:
Ionotropic:
- Nicotinic (multiple types) – similar to those at the NMJ
- Excitatory
Metabotropic:
- Muscarinic (multiple types) – excitatory or inhibitory
Describe Glutamate receptors:
ALL EXCITATORY!
Ionotropic
- AMPA receptors
- NMDA receptors
- Kainate receptors
Metabotropic
- Some couple to ↑ cAMP via Gs
- Some couple to ↑ IP3 and DAG via Gq
Describe GABA receptors:
Ionotropic:
- GABAA receptors (inhibitory)
- Ligand-gated Cl- channels
Metabotropic:
- GABAB receptors (inhibitory)
(Most couple to ↓ cAMP and ↑ K+ permeability (opening K+ channels) via Gi)
Describe Serotonergic Receptors:
Ionotropic:
- 5-HT3 receptors (excitatory)
Metabotropic:
- 5-HT1, 5-HT2, 5-HT4-7 (excitatory and inhibitory)
- Some couple to ↓ cAMP via Gi
- Some couple to ↑ cAMP via Gs
- Some couple to ↑ IP3 and DAG via Gq
(both expressed widely in the brain)
Describe adrenergic receptors:
Ionotropic
- none
Metabotropic
- a1 couple to ↑ IP3 and DAG via Gq
- a2 couple to ↓ cAMP via Gi
- B couple to ↑ cAMP via Gs
(expressed widely in the brain, both pre- and postsynaptically)
Describe dopamine receptors:
Ionotropic
- none
Metabotropic
- D1 (excitatory)-like couple to ↑ cAMP via Gs
- D2 (Inhibitory)-like couple to ↓ cAMP via Gi
(expressed widely in the brain, both pre-and postsynaptically)
Which of the following neurotransmitters do NOT bind to ionotropic receptors?
A. Acetylcholine
B. Glutamate
C. Serotonin
D. Norepinephrine
D. Norepinephrine
Catecholamines have ONLY metabotropic receptors (includes EPI)
In addition to the major neurotransmitters there are many other neurotransmitters and neuromodulators including _____ such as endogenous opioids, soluble gases such as _____, and ____ soluble molecules such as cannabinoids.
In addition to the major neurotransmitters there are many other neurotransmitters and neuromodulators including neuropeptides such as endogenous opioids, soluble gases such as nitric oxide, and lipid soluble molecules such as cannabinoids.
