Lecture 4.2: Synthesis, Packaging & Termination of NTs

Question 1

What are the five different subclasses of small molecule NTs?

Answer 1

Five different subclasses of small molecule NTs:

AMGGP

1. Ach
2. Monoamines (dopamine, Epi, NE, Histamine)
3. Glutamate
4. GABA and Glycine
5. Purines, ATP

Question 2

What are the three large categories of NTs?

Answer 2

Categories of NTs:

1. Classical or small molecule NTs (five subclasses of ACh, Monoamines, Glutamate, GABA and Glycine, and Purines)
2. Small peptides
3. Gases (like NO and CO)

Question 3

What NTs fall into these various categories:

Fast transmission, slow transmission, modulatory transmission?

Rate the speed of various NT type receptors: Ionotropic, Peptides, Metabotropic and ELectric

Answer 3

Fast transmission: nACh, glutamate

Slow transmission: mGLUR, catecholamines

Modullation: various types, peptides

Speed:

Electrical >>>>> Ionotropic (Ach/AA’s) >>>>> Metabotropic (GPCRs) >>> Peptides

Question 4

What are the classical criteria to be a NT?

Answer 4

Classical criteria to be a Neurotransmitor:
NT has to be synthesized, present and released from the nerve terminal

Question 5

What are the two NTs that participate in every neuronal circuit?

Answer 5

The two NTs that participate in every neuronal circuit are GABA and glutamate

Question 6

Describe the function of these various NTs:
Histamine

GHRH

Substance P

Answer 6

Histamine: present in one brain nucleus only (TM) coordinates the brain sleep wake cycle

GHRH: stimulates the release of growth hormone from the pituitary

Substance P: pain transmission, emesis

Question 7

Explain the Ionotropic and Metabotropic Receptors for these various NTs:
Ach

Glutamate

GABA

Glycine

Answer 7

NT Ionotropic Metabotropic

Ach—————–> Nicotinic—————–> Muscarinic

Glutamate———> GLUR——————–> mGLUR

NMDAR

GABA—————> GABAa——————> GABAb

GLycine————> Glycine

Question 8

Where are the following types of NTs synthesized?

Low MW NTs (small molecule NTs)

Gases

What increases synthesis of NTs?

Answer 8

Low MW NTs are synthesized locally, at the synaptic terminal they are released from

Gases are synthesized in dendrites or spines

An important modulator of synthesis is neuronal activity, increased activity will increase synthesis of NTs

Question 9

What is the concentration of NTs within vesicles?

Where does the energy to package NTs into vesicles come from?

Answer 9

Concentration of > 1 M within vesicles

Energy is provided by proton ATPase, which is why the pH in vesicles is very acidic

Question 10

What are the names of the five transporters that package the 5 subclasses of small NTs?

Answer 10

VAchT (vesicular ACh transporter)

VMAT (vesicular monoamine transporter)

VGLUT (vesicular glutamate transporter)

VIAAT (vesicular inhibitory AA transporter, aka GABA and glycine)

VNUT (vesicular nucleotide transporter aka ATP)

Question 11

Only ____ and _____ are packaged into vesicles

Peptides are packaged into vesicles at the ___

Answer 11

Only hormones and NTs are packaged into vesicles

Peptides are packaged into vesicles at the soma