Neurotransmitters

Question 1

What are the 5 criteria of a neurotransmitter

Answer 1

synthesis:
must be made in pre-synaptic neuronal 
storage:
presynaptically 
but not nitrous oxide 
release:
must be released on demand 
inactivation:
must be inactivated

Question 2

Main classifications of NT

Answer 2

amino acids
biogenic amines
peptides

Question 3

examples of amino acid NT

Answer 3

glutamate
GABA
Glycine

Question 4

two classes of biogenic NT

Answer 4

catecholamines:
noradrenaline 
adrenaline 
dopamine 
indolamines:
serotonin

Question 5

glutamate

Answer 5

primary excretory NT in the CNS
involved in memory, learning and cell death
postsynaptically via inonotropic receptors

Question 6

GABA

Answer 6

inhibitory NT in the CNS

acts via chloride channels

Question 7

Glycine

Answer 7

inhibitory NT in the CNS

but is primary in the spinal cord and brainstem

Question 8

`What are the three types of glutamate receptors

Answer 8

NMDA 
-Calcium ions 
Kainate 
-sodium and potassium ions
AMPA 
-permeable to cations (calcium, sodium and potassium)

Question 9

(dys)functions of glutamate

Answer 9

• synaptic plasticity
  synapses are strengthened or weakened by feedback mechanisms
• excitotoxicity
  excessive stimulation of NMDA receptors causes a large influx of calcium ions, can result in cell death
  -migraine
  Karl Lashleys visual aura, implicated in cortical spreading depression

Question 10

tell me about the causes epilepsy

Answer 10

excess excitation causes a feedback loop
uncontrolled excitation over expanding areas in the brain
can begin as partial seizures, if they become more uncontrolled, can become gran Mal seizures

Question 11

What can seizures be treated with

Answer 11

phenytoin
- increases the refractory period between firings in voltage gated sodium channels

benzodiazepines
increase the action go GABA (because its an inhibitory NT)

Question 12

Benzodiazepines

Answer 12

act on a separate receptor binding site on the GABA receptor subtype than GABA..
This controls the a ability of GABA to open the channel as when its bound the channel can open more frequently.

Question 13

GABA

Answer 13

Found predominantly in the interneurons of the CNS - modules depending motor information
Acts on ligand gated chloride channels
Inactivated by presynaptic reuptake

Question 14

Tell me about alcoholism

Answer 14

causes a change in GABA transmission, withdrawal results in convulsive movements and seizures
Can be treated with benzodiazepines and phenytoin

Question 15

Glycine

Answer 15

second most common inhibitory NT in the CNs

But has major effects in the spinal cord and brainstem

Question 16

Tell me about tetanus

Answer 16

caused by toxin clostridium tetani
inhibits the release of glycine
-shifts excitation-inhibition balance
mild effects restricted to muscles innervated by cranial nerves
more serious effects include epileptiform fits
treated with anti-toxin and benzodiazepines

Question 17

dopamine

Answer 17

NT and neuromodulator

involved with pleasure , addition and movement

Question 18

noradrenaline

Answer 18

sympathetic fight or flight response NT

decrease potentially associated in Parkinson’s and ADHD

Question 19

Adrenaline

Answer 19

sympathetic
peripheral hormone from adrenal medulla
SYNTHESISED IN THE BOUTON AND INACTIVATED PRINCIPALLY BY RE-UPTAKE

Question 20

Effects of dopamine

Answer 20

parkinsons
tremor, muscle rigidity due to depleted dopamine in the motor coordination circuits
schizophrenia
over production of dopamine in the mesolimibic system
Addiction
works through pleasure centres of the CNS located in the mesolimbic dopamine system

Question 21

effects of serotonin

Answer 21

depression and OCD

can be treated with fluoxetine as this is a serotonin reuptake inhibitor

Question 22

effects of endorphins and encephalins

Answer 22

pain
act on opioid receptors and endogenous ligands , opioids cause the down regulation of opiod receptors in the CNS
leads to opioid tolerance and increased intake

emotional perception:
naloxone can reduce symptoms

Question 23

acetylcholine - esters

Answer 23

found in both PNS and CNS (neuromuscular junction)
CNS:
-neurons project to the hippocampus and cortex
regions essential for the formation of new memories and learning

Question 24

Alzheimers disease

Answer 24

associated with dysfunction (reduction/) of ACh in the CNS

Question 25

Nicotine

Answer 25

acts on nicotinic acetylcholine receptors found in the PNS and the CNS

Question 26

Anticholinesterases

Answer 26

prevent breakdown of ACh therefore prolonging its activity

Can be therapeutic but also toxic