neuro

Question 1

AchE- Acetyl choLine esterase

Answer 1

Target of nerve gases sarin, insecticides, drugs ( physostigmine- glaucoma) In the synapse released made in the postsynaptic neuron

Question 2

Tyrosine Hydroxylase

Answer 2

RLS - Rate limited enzyme Catchecholamines Synthesis Tyrosine–> LDOPA

Question 3

AADC Aromatic Amino acid Decarboxylase

Answer 3

AADC= L-DOPA 5- Hydroxytryptophan–> 5’ HydroxyTryptamine

Question 4

COMT

Answer 4

Catechola-O-methyltrasnferase Liver, PNS

Question 5

MAO

Answer 5

Mitochondrial Monoamine oxidase

Question 6

PNMT

Answer 6

Phenylethanolamine-N_methyltrasnferase NE–> E in the cytoplasm Site: Only in epinephrine neurons and Adrenals

Question 7

SERT

Answer 7

Serotonin re-uptake inhibitors Target of SSRIs

Question 8

Ionotropic Vs Metabotropic

Answer 8

Ionotropic- ligand gated- causes a conformational change leading to ion channel opening

Fast msec

direct gating

ion selectivity- size and charge

Kinetics of binding, how wide channel opens, ions conc

Metabotropic- GPCR- no channel- confirmational change

indirect gating of an ion channel ( not directly through there channel However)

2nd messenger cascades

slower -longer lasting

even change in transcription

Question 9

ChAT.

Answer 9

Choline + acetyl CoA ——> choline acetyltransferase (ChAT) —> acetylcholine (ACh). Choline is produced endogenously in the liver and by membranes RLS_ the amount of choline that is available in the presynaptic neuron is the rate limiting factor for the production of ACh.

Question 10

Norepinephrine

Answer 10

Only NT made in the vesicles identifies NE neurons Dopamine Beta- hydroxylase DA-Beta- (DBH) Dopamine–> NE

Question 11

L-Tyrosine

Answer 11

Hydroxyphenylalanine Catecholamine Synthesis precursor L-tyrosine— ( tyrosine- hydroxylase- RLS) > L Dopa

Question 12

Catecholamines Synthetic Pathway

Answer 12

Tyrosine Hydroxylase is the Rate Limiting Step

Question 13

Question 14

Serotonin (5-HT) Synthesis, Release & Inactivation

Answer 14

1. Active transport of tryptophan into cell
2. Tryptophan converted to 5-hydroxytryptophan by tryptophan-5-hydroxylase (rate limiting step)
3. 5-hydroxytryptophan is converted to serotonin (5-HT; 5-hydroxytryptamine) by aromatic L-amino acid decarboxylase (AADC)
4. Serotonin is actively transported into the storage vesicles
5. Ca2+ mediated exocytosis/release of 5-HT; NT diffuses across the cleft and binds to its postsynaptic receptor
6. Re-uptake/removal of serotonin by specific presynaptic transporter (SERT)
7. Serotonin is metabolized by mitochondrial MAO or reloaded into vesicles.

Question 15

Metabotropic Receptors

Answer 15

Indirect gating

Can direct the flow of ions

Ions DONOT flow through***

Dont directly form ion pores

cause opening of a neighboring ion channels

Ie Muscarinic AchR

Question 16

Ionotropic Receptors

Answer 16

Ligand- Gated ion channel

Direct gating

Same receptor - binds ligand- then the channel opens for the ion

ie- Nicotinic Receptor AcHR on the SKELETAL muscles to get a quick response

Question 17

Sympathetic & Parasympathetic NTs and Receptors

Answer 17

Note in this diagram that CNS neurons innervate muscle directly while other CNS neurons synapse onto specific ganglia or chromaffin cells in the adrenal glands. Take special note of the NTs released at each synapse and the respective receptors present on the post-synaptic cells.

Important for this block, chromaffin cells are neuroendocrine cells found mostly in the medulla of the adrenal glands. Notice that sympathetic neurons (presynaptic cell) release ACh onto chromaffin cells (postsynaptic cell) which express nicotinic receptors. Activation of nicotinic receptors causes the release of E/adrenaline and NE/noradrenaline from the chromaffin cells into the circulation, where these NTs affect multiple organs.

NOTE: postsynaptic cells innervated by sympathetic neurons/chromaffin cells express nicotinic receptors (ionotropic) while postsynaptic cells innervated by parasympathetic neurons can have muscarinic receptors (GPCRs)

Question 18

Serotonin (5-HT) influences peripheral tissues

Answer 18

Serotonin (5-HT) is a NT that has CNS and peripheral targets.

It is important in the regulation bone remodeling (SSRI’s decrease bone density), lipolysis, glucose metabolism, bone marrow and gut microbiome.

TPH1 - receptor for 5 HT ??

Question 19

Sympathetics

Answer 19

Sympatheitcs T1-L2

• One of 3 routes:
  
  • Sympathetic chain ganglia
  • Collateral ganglia
  • Adrenal Gland
• All have Nicotinic Receptors–> quick Response–> Ionotropic***

Question 20

Input

Afferent

PNS

Answer 20

Dorsal Alar Pate

Question 21

Output

Efferent

PNS

Answer 21

Motor Neurons In the Basal Plate

output to

• Autonomic ganglia
• Motor nerves