Ch. 6 Nervous System Pt. 4 (Neurotransmitters)

2 types of toxins?

1) tetanus toxin

2) toxin that causes botulism

tetanus toxin effect?

destroy SNARE protein→block release of inhibitory neurotransmitters→excess muscle contraction/lock jaw

effect of the toxin that causes Botulism?

destroys SNARE protein→block Ach(excitatory neurotransmitter)→reduced muscle contraction/paralysis

What 3 drugs/toxins can inhibit an action potential?

1) local anesthetics

2) puffer fish TTX(tetrodotoxin)
3) Poison dart drog BTX(batrachdotoxin)

What do local anesthetics do? What are 2 clinical drug examples?

-block voltage-gated Na+ channels=no action potential
1) Procaine

2) Lidocaine

Effect of Puffer fish TTX?

block Na+ channels from opening=no depolarization→death

Effect of poison dart frog BTX?

keep Na+ channels open=no depolarization→death

Cholinergic Neurons

neurons that use Ach has a primary neurotransmitter

Degeneration of cholinergic neurons leads to what?

less Ach in brain=Alzheimer’s disease

What receptors does AcH bind to?

1) Muscarine (GPCR)

2) Nicotinic (Ion channel)

Where are nicotinic receptors found in the human body?

neuromuscular junctions of the skeletal muscle

what produces Ach?

enzyme Choline Acetyl Transferase(CAT)

-Acetyl Coa+Choline=Acetylcholine+CoA

which enzyme breaks down Ach?

acetylcholinesterase(AchE)

Acetylcholine→acetate+choline

What does the nerve gas Sarin do

blocks AchE(Acetylcholinesterase)→increased muscle contractions & paralysis

Neuromodulator vs. Neurotransmitter

Neuromodulator→modifies postsynaptic cell’s response to neurotransmitter over time

(associated w/ slower events like learning/ development)

Neurotransmitter→ involved in rapid communication

Biogenic Amine Neurotransmitters

1) Catecholamines( Epinephrine, Norepinephrine, Dopamine)

2) Serotonin

3) Histamine

Which amino acid produces Catecholamines, Serotonin, & Histamines?

Catecholamines→tyrosine

Serotonin→tryptophan

Histamine→histidine

which enzymes degrade Biogenic Amine neurotransmitters?

1) MAO
2) COMT

What type of receptor does Epinephrine & Norepinephrines use?

Adrenergic Receptors

-Alpha 1, 2

-Beta 1,2,3

What is the effect of Norepinephrine in the PNS & CNS?

PNS→increase blood pressure & constrict arteroiles
CNS→alertness/ arousal

What drug increases norepinephrine activity?

amphetamines

What are 2 types of Dopamine Systems? I guess you can say 3 Systems

1) Nigrostriatal
2) Mesocorticolimbic

a) mesolimbic -reward learning, motivation, emotion
b) mesocortico- cognition, attention, executive function

Nigrostriatal Dopamine System function? Disease involved?

-motor control
degeneration of this system=Parkinson’s

Mesocorticolimbic Dopamine System function? Diseases involved?

-reward, motivation, emotion

too much dopamine=addiction+schizophrenia

What are the Amino Acid Neurotransmitters?

1) Glutamate

2) Glycine
3) GABA

Glutamate neurotransmitter

-excitatory

-memory(LTP-long term potentiation) & learning

how does glutamate neurotransmitter help with memory?

glutamate binds to AMPA & NMDA receptor→open Na+ channels & Ca2+ channels→LTP

Glycine neurotransmitter

-inhibitory

-opens Cl- channels

-control skeletal movements

GABA neurotransmitter

-most prevalent inhibitory neurotransmitter in brain

-motor function & neuronal excitability

Neurotransmitters that fall under Neuropeptides?

1) Endogenous opioids (pain-related)

2) Glucagon-like peptide 1

Glucagon-like peptide 1 effect?

insulin-related & appetite-related

Gaseous Neurotransmitter?

Nitric Oxide

1) release macrophages

2) memory learning

3) muscle relaxation

What drug blocks neurotransmitter release at synapse?

Botox destroys SNARE proteins & block Ach vesicle fusion

Which drugs block neurotransmitter reuptake in the synapse?

1) Zoloft

2) Lexapro

(SSRI’s that block serotonin reuptake)

Which drugs bind to postsynaptic receptors as an antagonist or agonist in synapse?

1) Haloperidol →block D2 Dopamine receptors (antagonist)

2) Nicotine→activate Nicotinic Ach receptor (agonist)

Where is serotonin produced & found in the body?

1) 1-2% is in the brainstem(raphe nuclei)
2) 90% produced by enterochromaffin cells in the gut (does not interact w/ brain)

what is Serotonin also called?

5-HT

functions of Serotonin

1) sleep

2) emotions

3) appetite
4) sex behavior

5) pain & sensory processing

6) excessive serotonin release=diarrhea (appetite )

what do SSRI’s treat?

depression & a bunch of other disorders

During a stroke, too much of ______neurotransmitter is released?

glutamate

side effects of Zoloft in adults & kids?

adults:

-nausea, sweating, tremor, tired

-sleep/sex issues

kids:

-slow growth rate(height & weight must be monitored)

Psychoactive Substances

1) Ibogaine

-from African Iboga Shrub
-related to addiction & symptoms related to PTSD, depression, anxiety
2) 5-MeO-DMT

-acts on serotonin receptors