Neurochemicals 2

Question 1

AMINES

Answer 1

• Acetylcholine

Question 2

MONOAMINES

Answer 2

• Catecholamines (Dopamine, Norepinephrine, Epinephrine)
• Indolamines (Serotonin, Melatonin)
• Histamine

Question 3

AMINO ACID

Answer 3

Glutamate, GABA, 6 others

Question 4

Neuropeptides

Answer 4

• Endorphins
• Substance P
• Cholecystokinin
• Insulin
• Vasopressin
• Oxytocin
• More than 40 others…

Question 5

Gaseous NT

Answer 5

• Nitric oxide
• Carbon monoxide?

Question 6

Peptides

Answer 6

• short chains of amino acids.

Question 7

neuropepdies and found in and released from:

Answer 7

cell body and axon terminal

Question 8

Neuropeptides are cleaned up by

Answer 8

Diffusion and enzymes

Question 9

Opium contains

and they bind to:

Answer 9

• morphine, an effective analgesic or painkiller.
• These opiates bind to opioid receptors in the brain, especially in the locus coeruleus and periaqueductal gray.

Question 10

Naloxone

Answer 10

• opiate antagonist – reverses opiate overdose/intoxication. Can revive from coma in 30 seconds. Important for research, to identify opiates and receptors.

Question 11

Analgesia

Answer 11

• Relief of pain) – by activating Peri-Aqueductal Gray  inhibits pain neurons in spinal cord by inhibiting release of Substance P on slow-pain fibers.

Question 12

Nitric oxide (NO)

Answer 12

• A gas that performs a type of signaling between neurons and is also involved with the maintenance of blood pressure.
• NO play an important role in regulating communication between the thalamus and the cerebral cortex.

Question 13

Nitric oxide is broken down by

Answer 13

enzymes

Question 14

Neuromodulators

Answer 14

• Modulate (make stronger or weaker) the effectiveness of those excitatory and inhibitory neurotransmitters.

Question 15

Acetylcholine serves what and is considered what

Answer 15

• Both a neurotransmitter and a neuromodulator
• Neurotransmitter for 10-15% of neurons in nervous system: all voluntary neuromuscular junctions, many nerve-gland synapses, Autonomic Nervous System

Question 16

Acetylcholine synthesis and breakdown

Answer 16

• ACh is produced by the presynaptic neuron and released into the synapse.
• CoA- coenzyme (molecule that acts an enzyme) which is important in fatty acids + a molecule called choline () that we absorb from food+ choline acetyltransferase (CHAT)=ACH
• in short: COA+Choline+CHAT=ACH
• Breakdown:​
  
  • AChE- acetylcholinesterase+ acetic acid (vinegar) +choline= get rid of it (terminates signal transmission)

Question 17

The life cycle of Acetylcholine (Ach)

Answer 17

• We see in the PRE acetylcholine bring produced with choline+ COA with CHAT enzyme makes ACH. Packed into vesicles. Exocytosis in gap. Once it binds to Postsynaptic receptor, we get rid of it via enzyme which is found in the gap (produced in the presynaptic cell)
• Then ACH+ ACHE + Choline + acetic acid=goodbye Mr. ACh

Question 18

major and minor sources of ACh

Answer 18

major- Basal forebrain

minor- Pedunculopontine nucleus

Question 19

destination of ACh

Answer 19

hippocampus

Question 20

Two types of Acetylcholine receptors

Answer 20

• Nicotinic – most are ionotropic and excitatory
• Example: muscles use nicotinic ACh receptors – paralysis can be induced with an antagonist, such as curare.
  
  • Enhances memory +cancer
  • Antagonists bind to them cura-care and atropine
• Muscarinic – are metabotropic and can be excitatory or inhibitory
• Muscarinic ACh receptors can be blocked by atropine or scopolamine to produces changes in cognition.
• Named after stuff that binds to them

Question 21

Myasthenia Gravis illness and treatment

Answer 21

• auto-immune disorder that attacks neuromuscular ACh receptors.
• Treatment: Neostigmine – an AChE inhibitor. Does not pass the blood-brain barrier, so effects are peripheral.

Question 22

Botox Treatment

Answer 22

• of botulinum toxin type A decreased muscle activity by blocking the release of acetylcholine at the neuromuscular junction, by deactivating the protein that causes docked synaptic vesicles to fuse with the pre-synaptic membrane and expel its contents - thereby rendering the muscle unable to contract for a period of 3 to 4 months.

Question 23

Nerve Gas damage and treatment

Answer 23

• blocks AChE causes diaphragm contraction, death by asphyxiation
  
  • With this ach keeps binding to receptors without presynaptic saying so, therefore it contracts it so many times
    
    • Atropine syringe- synaptic blocker stopping the contraction.

Question 24

What does Acetylcholine do?

Answer 24

• Areas that produce Acetylcholine receive input from Prefrontal Cortex or other brain areas.
• Acetylcholine activates Cerebral Cortex and controls electrical rhythms of Hippocampus: Facilitates attention, learning and memory, etc.

Question 25

Alzheimer’s Disease and Acetylcholine

Answer 25

* _Alzheimer’s Disease (AD) – deficiency in ACh (Acetylcholine) more than in other neurotransmitters, because_: * Specific degeneration of the **Nucleus Basalis of Meynert**, where ACh is produced. * In Alzheimer’s: Ach goes to hippocampus as the hippo is the target. In alz though there is an issue with the Ach and therefore the hippo, where memory is kept, is affected

Question 27

Catecholamine neurotransmitters definition and is produced from:

Answer 27

* Contain a chemical group called catechol group * Produced from same amino acid called tyrosine (TH) * Produced from same amino acid called tyrosine (TH) (DON’T NEED TO KNOW ENZYMES) + enzyme modifies to make a think called el DOPA

Question 28

Dopamine is important for

Answer 28

* for lots of things from movement to reward since different brain locations or networks

Question 29

* 2 pathways for dopamine

Answer 29

* **_Mesotimbocortical pathway-_** goes from substnia nigra to striatum * DA in this pathway is involved in reward, reinforcement and learning. Abnormalities are associated with schizophrenia. * **_Mesostriatal pathway-_** The Meso-striatal pathway is important in motor control, and neuronal loss is a cause of Parkinson’s disease.

Question 30

Dopamine (DA) – its motor functions

Answer 30

* Motor areas (e.g., basal ganglia), DA generally facilitates voluntary movements. * Voluntary movements impaired in Parkinson’s Disease.

Question 31

Norepinephrine (NE)

Answer 31

* NE is also known as *noradrenaline* – cells producing it are **noradrenergic** * **Adrenaline = Epinephrine** * * Noradrenergic fibers from the **locus coeruleus** project broadly through the brain. * The CNS has four subtypes of NE receptors – all metabotropic. * The NE systems modulate processes including **mood, alertness, arousal, and sexual behavior.**

Question 32

Serotonin (5-HT)

Answer 32

* Serotonin (5-Hydroxytriptamine) - 90% of this chemical in the body is in the gut – regulates intestinal movements… * In the brain – regulates mood, appetite, sleep sexual behavior, and anxiety. * Almost all serotonin receptors are metabotropic, activating an intracellular “second messenger” cascade.

Question 33

Serotonergic Pathways in the Brain

Answer 33

* Only 100,000 serotonergic neurons in the brain – but at least 15 different receptor types! * Dorsal Raphe Nuclei (DRN) does not receive inputs of direct primary motor or sensory cortices. Virtually all cortical inputs are from ventro-medial prefrontal cortex – an area of the brain important for emotional cognition. Central nucleus of the Amygdala (fear processing) also projects to DRN. * Example: DRN release 5-HT when we experience sustained noxious stimuli during stressful conditions. Uncontrollable stress detected by ventro-medial prefrontal cortex activates DRN to release 5-HT, leading to *learned helplessness* behaviors.

Question 34

serotonin after release

Answer 34

* is reuptaken into the releasing neuron and repackaged or metabolized by Monoamine Oxidase (MAO). * So some of the first _anti-depressants_ were MAO inhibitors – but since they don’t only act on Serotonin, they have lots of side effects. ## Footnote **Antidepressants such as Prozac are Selective Serotonin Reuptake Inhibitors (SSRI) -increase 5-HT activity, with effects depending on which receptor subtype is affected**

Question 35

Neuropeptides Substances

Answer 35

1. Substance P- 2. Endorphins/Morphine 3. Insulin and Cholecystokinin

Question 36

Substance P

Answer 36

perception of pain

Question 37

Endorphins/Morphine

Answer 37

act on same receptors as opioids like herion

Question 38

Insulin and Cholecystokinin

Answer 38

digestion, process nutrients. Neuromodulating and neurohormone functions

Question 39

Gasotransmitters Substances

Answer 39

* NO, CO, H2S- transfer information from one cell to another * NO is produced by NOS found in a small number of neurons * NO is used for neural communication, blood pressure, and erection * Viagra boosts NO * NO activates second messengers within neurons * leading to probable roles in learning and memory, anxiety, and addiction * too much NO is toxic and can cause psychological disorders like schizophrenia * regulates communication between the thalamus and cerebral cortex which influences the amount of sensory input processed by higher levels of the brain * Act on receptors located within cells * Breakdown quickly without action of enzymes

Question 40

Agonists and antagonists Reserpine and Methamphetamine

Answer 40

* **_Agonists_**- enhance activity of neurochemicals * **_Antagonists_**- reduce activity of neurochemicals * **_Reserpine_**- a drug used to reduce blood pressure and psychosis, interferes with the uptake of monoamines into synaptic vessels... * Respirenes interference with serotonin often results in depression * **_Methamphetamine_**- dopamine agonist * Taken up by dopamine transporters * When it arrives to axon terminal the Methamphetamine displaces dopamine in the vesicle * High concentration of dopamine in the intracellular fluid disturbs actions of transporters and pumps dopamine intpo the gap and it interacts with post synaptic receptors all without an AP

Question 41

Botulism

Answer 41

a fatal condition produced by bacteria in spoiled food, a toxin produced by the bacteria prevents a release of Ach

Question 42

Curare

Answer 42

* - blocks Ach (nicotinic receptors) * Similar to snake venom

Question 43

Barbiturate

Answer 43

* GABA agonist, tranqilizer (valium) * Like alcohol, and both only increase response to GABA A, when the GABA is present

Question 44

Barbiturate-

Answer 44

* - GABA agonist, strong sedation drug (anestesia), helps with seizures * can activate GABAa receptor without having any GABA a present * ALL GABA AGONISTS increase inhibition * Too much alchohol, Barbiturate or Barbiturate, can be life threatening amount of inhibition

Question 45

Area postrema

Answer 45

* a brain stem area in which the blood brain variable is more permeable that triggers a vomiting response to toxins

Question 46

Placebo tolerence/withdrawl

Answer 46

* Placebo effect- preceived benefit from inactive substances * Double blind experiment- neither the participant or the experimenter knows if the participant is receiving a drug or a placebo **_Tolerance_**-the process in which more of a drug is needed to produce the same effect as a result of repeated administration **_Withdrawal_**- the symptoms that occur when a certain addictive drug is no longer administered or are administered in smaller quantities