Neurotransmitters

Question 1

What are the major neurotransmitters?

Answer 1

1. Acetylcholine
2. Amino Acids

• Glutamate
• GABA
• Glycine

3. Amino acid derived

• Serotonin
• Catecholamines
  
  • norepinephrine
  • dopamine

Question 2

______ _____ Neurons use ACh as a modulator of motor coordination.

Answer 2

Basal Ganglia Neurons use ACh as a modulator of motor coordination

Question 3

Basal Nucleus of Meynert neurons in basal forebrain synthesize ____ (these axons project widely in the cortex facilitating memory).

Answer 3

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.)

Question 4

_____ is the major excitatory neurotransmitter in the CNS.

Answer 4

Glutamate is the major excitatory neurotransmitter in the CNS.

Question 5

Glutamate is often implicated in “_______” in which neurons under stress die when overly excited.

Answer 5

Glutamate is often implicated in “excitotoxicity” in which neurons under stress die when overly excited.

Question 6

Where in the body does glutamate act? What is its mechanism of action?

Answer 6

Acts everywhere: Spinal cord, brain stem, cerebellum, hippocampus, cerebral cortex

Excitation of cognitive, motor and sensory function

Question 7

____ is the major inhibitory neurotransmitter in the CNS.

Answer 7

GABA is the major inhibitory neurotransmitter in the CNS.

Question 8

Where is GABA found in the body? What is its mechanism of action?

Answer 8

Found predominantly in interneurons - located throughout the CNS

Sedation & muscle relaxation, cardiovascular and respiratory function, spinal reflexes, pain perception

Question 9

_______ bind to the GABA receptor complex and enhance its inhibitory actions on neural activiy.

Answer 9

Benzodiezopines bind to the GABA receptor complex and enhance its inhibitory actions on neural activiy.

Question 10

Benzodiezopines bind to the ____ receptor complex and enhance its inhibitory actions on neural activiy.

Answer 10

Benzodiezopines bind to the GABA receptor complex and enhance its inhibitory actions on neural activiy.

Question 11

Glycine is a(n) ______ neurotransmitter in the CNS.

Answer 11

inhibitory

Question 12

Where does glycine act in the body?

Answer 12

Everywhere - spinal cord interneurons

Question 13

Where is serotonin produced? What does it act on/control?

Answer 13

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)

Question 14

Serotonin neurotransmission is enhanced by drugs which inhibit reuptake of serotonin into the ______ neuron (SSRIs=Selective Serotonin Reuptake Inhibitors).

Answer 14

Serotonin neurotransmission is enhanced by drugs which inhibit reuptake of serotonin into the presynaptic neuron (SSRIs=Selective Serotonin Reuptake Inhibitors).

Question 15

Endogenous examples of catecholamines:

Answer 15

Dopamine

Norepinephrine

Epinephrine

Question 16

Where does the locus ceruleus project to?

Answer 16

Much of the cortex mediating arousal, attention, and anxiety

Question 17

List 3 important catecholamines and 1 important synthetic enzyme:

Answer 17

Dopamine

Norepinephrine

Epinephrine

Tyrosine hydroxylase

Question 18

_____ neurons synthesize dopamine and project axons to the ____.

Answer 18

Substantia nigra neurons synthesize dopamine and project axons to the basal ganglia.

Question 19

Substantia nigra neurons synthesize _____ and project axons to the basal ganglia.

Answer 19

dopamine

Question 20

Depletions in dopamine are connected to _____ (disease) and elevations in dopamine are connected to ____ (disease).

Answer 20

Depletions in dopamine are connected to Parkinson’s (disease) and elevations in dopamine are connected to Schizophrenia (disease).

Question 21

Ionotropic channel characteristics:

Answer 21

Receptor is also an ion channel

Question 22

Metabotropic channel characteristics:

Answer 22

Receptor activation triggers second messenger pathways:

Question 24

Excitatory ionotropic receptors include those for: (4)

Answer 24

Glutamate

Acetylcholine

5-HT (serotonin)

ATP

Question 25

Excitatory ionotropic receptors are ____ selective, whereas inhibitory ionotropic receptors are ___ selective

Answer 25

Excitatory ionotropic receptors are **cation** selective, whereas inhibitory ionotropic receptors are **anion** selective

Question 26

Inhibitory ionotropic receptors include (2):

Answer 26

GABA Glycine

Question 27

Describe acetylcholine receptors:

Answer 27

**Ionotropic:** * Nicotinic (multiple types) – similar to those at the NMJ * Excitatory **Metabotropic:** * Muscarinic (multiple types) – excitatory or inhibitory

Question 28

Describe Glutamate receptors:

Answer 28

**ALL EXCITATORY!** **Ionotropic** * AMPA receptors * NMDA receptors * Kainate receptors **Metabotropic** * Some couple to ↑ cAMP via Gs * Some couple to ↑ IP3 and DAG via Gq

Question 29

Describe GABA receptors:

Answer 29

**Ionotropic:** * GABA_A receptors (inhibitory) * Ligand-gated Cl- channels **Metabotropic:** * GABA_B receptors (inhibitory) (Most couple to ↓ cAMP and ↑ K+ permeability (opening K+ channels) via G_i)

Question 30

Describe Serotonergic Receptors:

Answer 30

**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)*

Question 31

Describe adrenergic receptors:

Answer 31

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)*

Question 32

Describe dopamine receptors:

Answer 32

**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)*

Question 33

Which of the following neurotransmitters do NOT bind to ionotropic receptors? A. Acetylcholine B. Glutamate C. Serotonin D. Norepinephrine

Answer 33

D. Norepinephrine Catecholamines have ONLY metabotropic receptors (includes EPI)

Question 34

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.

Answer 34

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.