ch.3 - neurotransmission

what maintains the resting state

sodium potassium pump

• 3 Na out 2K in

potassium leak channels

• K out

action potential

• Na+ rush in

• delay then K+ out

absolute refractory period

1-2 milliseconds CANT produce ap

• K+ exit

• Na closed

relative refractory period

2-4 milliseconds

• Na+ could reopen with strong enough stimulation

what proteins do synaptic vesicles fuse to

SNARE proteins

NT binding to receptors triggers…

EPSP

• Na or Ca

IPSP

• K or Cl

3 methods of termination

• diffusion

• degredation

• reuptake

are pre and post syn receptors excitatory or inhibitory

both but pre syn more inhibitory

2 types of pre synaptic receptors

autoreceptors

• same NT from axon terminal

heteroceptors

• dif NT from axon terminal

ionotropic receptors

aka ligang gated

• fast transmission

metabotropic receptors

• g protein → dimer

• slow effects

amino acid NT

glutamte and GABA

essential a.a

must be consumed or microbio

glutamate synthesis

glutamine → glutamate

• glutaminase

• released by pyramidal neurons

glutamte ionotropic receptors

AMPA, NMDA, kainate

• excitatory

glutamate metabotropic receptors

mGlu

• group 1: excitatory

• group 2 and 3: inhibitory

GABA synthesis

glutamte → GABA

• glutamate decarboxylase

GABA receptors

all inhibitory

• GABA A → ionotropic

• GABA B → metabotropic

GABA removal

gaba amino transferase

monoamine NT

catecholaminess

• dopamine, NE, EPI

indoleamines

• serotonin

dopamine synthesis

phenylalanine → tyrosine → L-dopa → DA

dopamine is brought to vesiclses by…

VMAT

dopamine receptors

ALL metabotropic

• D1 and D5 → excitatory

• D2, D3, D4 → inhibitory

dopamien removal

catabolysis

• MAO (pre syn)

• COMT (post syn)

dopamine transporters

mesolimbic pathway

VTA → nucleus accumbens → amygdala → hippocampus

• reward + motivation

mesocortical pathway

VTA → prefrontal cortex

• cognition + emotion

nigrostraital pathway

substantia nigra → basal ganglia

• movement affected in Parkinson’

tuberoinfundibular

hypothalamus → pituitary

• hormone regulation

NE and EPI synthesis

dopamine → NE → EPI

NE receptors

all metabotropic

all excitatory except alpha 2

• alpha 1, 2

• beta 1, 2, 3

removal of NE

• MAO

• COMT

• NE transporters

locus ceurelus is with…

NE

serotonin synthesis

tryptophan → 5 HTP → serotonin

serotonin receptors

5HT1 and 5HT5 → inhibitory

5HT3 → ionotropic

serotonin removal

SERT and MAO

Ach synthesis

choline + acetyl → Ach

what transports Ach to vesicles

vesicular Ach tanshpoters

cholinergic receptos

Nicotinic (ionotropic): excitatory Muscarinic (metabotropic):

• M1, M3, M5 → excitatory

• M2, M4 → inhibitor

neuropeptides

made in cell body

• Substance P – pain transmission.

• Endorphins – pain relief and reward.

• Oxytocin – social bonding, trust.

• Vasopressin – fluid regulation, social behaviour.

• Neuropeptide Y (NPY) – appetite and stress response

neurotrophins

promote survivla + plasticity by binding to receptor tyrosine kinase

• ie. BDNF