Exam 2: Nicotine Pt. 2

Question 1

nicotine is an agonist for…

Answer 1

nicotinic acetylcholine receptors (nAChR)

• binds to same place as Ach
• opens Na ion channels, excitatory response - depolarization
• high affinity receptors in brain and autonomic ganglia

Question 2

high doses of nicotine lead to persistent activation of …

Answer 2

nAChR and continuous depolarization of postsynaptic cell

Question 3

what is it when the cell cannot fire again until nicotine is removed

Answer 3

depolarization block

Question 4

acetylcholine actions of a new smoker

Answer 4

Ach actions increase following nicotine use

- no pharmacodynamic tolerance yet

Question 5

acetylcholine actions of an addicted smoker

Answer 5

brain compensates for amount of Ach by DECREASING the number of postsynaptic receptors (down regulation - form of pharmacodynamic tolerance)

Question 6

nAChRs found both presynaptically and postsynaptically, facilitate actions of what?

Answer 6

ACh, dopamine, serotonin, and glutamate

- has effects on CNS, PNS, heart and other organs

Question 7

nicotine activates sympathetic and parasympathetic systems causing…

Answer 7

wide range of physiological effects like tachycardia, and inc BP

Question 8

MAO in smokers

Answer 8

smokers have way less MAO
- MAO breaks down monoamines like dopamine and norepinephrine
- if not broken down, these are remaining in the synapse for longer
inhibition of MAOs contributes to reinforcing effects of smoking

Question 9

how does smoking affect the brain?

Answer 9

1. alters the number of receptors available (up/down regulation)
2. high affinity nAChR in the VTA stimulates firing of dopamine neurons which inc dopamine release in nucleus accumbens

Question 10

when nicotine binds you get more action potentials so….

Answer 10

dopamine levels inc in the nucleus accumbens

Question 11

what subunits are involved in nicotine reinforcement

Answer 11

a4, a6, B2

Question 12

what is linked to the subjective effects of smoking, smoking rates, and the risk of developing nicotine dependence

Answer 12

genetic polymorphisms for a4, a6, B2

more receptors-more likely to be pleasurable

Question 13

which subunits are involved in nicotine’s aversive properties - reducing the propensity to consume or self-administer

Answer 13

a5,a3,B4

Question 14

where are nAChRs that mediate nicotine aversion concentrated

Answer 14

medial habenula to the interpeduncular nucleus

Question 15

effects of nicotine: dopamine

Answer 15

pleasure, reward

Question 16

effects of nicotine: norepinephrine

Answer 16

arousal, appetite suppression

Question 17

effects of nicotine: acetylcholine

Answer 17

arousal, attention and cognitive enhancement (learning, memory)

Question 18

effects of nicotine: glutamate

Answer 18

learning, memory improvement

Question 19

effects of nicotine: serotonin

Answer 19

mood, appetite suppression

Question 20

effects of nicotine: B-endorphin

Answer 20

reduces anxiety and tension

Question 21

effects of nicotine: GABA

Answer 21

reduced anxiety and tension

Question 22

4 benefits of nicotine

Answer 22

• learning, memory, ability (positive influence on cognition and motor function even in nonsmokers)
• symptoms reduced in ADHD and Tourette’s (tics)
• Alzheimer’s disease (patients see Ach neurons die, but with nicotine they have inc capacity for learning verbal material - replaces the lost Ach input)

-PD: dopamine neurons die, with nicotine they have lower incidences of PD
(nicotine is neuroprotective for dopamine neruons)

Question 23

nicotine effects in smokers

Answer 23

• calm, relaxed state

- partly a relief from nicotine withdrawal symptoms

Question 24

nicotine effects in nonsmokers

Answer 24

elicits heightened tension or arousal
lightheadedness, dizziness, nausea
-here Ach is acting as a true stimulant

Question 25

acute effects of nicotine (7)

Answer 25

- general stimulant/arousal effects (inc HR and BP, alertness, appetite suppression) - carbon monoxide reduces O2 transport to heart and organs - calming (anxiolytic) effects in some (common users) - mild euphoria - cognitive enhancements - antidepressant effects - dec in MAO

Question 26

nicotine addiction cycle (6 steps)

Answer 26

1. cigarette smoking 2. nicotine absorption 3. arousal, mood modulation, pleasure 4. tolerance and physical dependence 5. drug abstinence produces withdrawal symptoms 6. craving for nicotine to self-medicate withdrawal symptoms

Question 27

during the night, mild withdrawal occurs, but at the same time tolerance from the previous day dissipates

Answer 27

acute tolerance

Question 28

acute tolerance is related to _____

Answer 28

desensitization of central nAChRs - including ones that mediate nicotine reinforcement `

Question 29

chronic tolerance to nicotine

Answer 29

- long term exposure - compensatory response in brain: upregulation of high affinity nAChRs - subjective nicotine effects occur with frequent use - slow to dissipate even after abstinence - nACR desensitization to blame

Question 30

what leads up to chronic tolerance?

Answer 30

wanting, craving, needing

Question 31

abstinence syndrome

Answer 31

long nicotine withdrawal | symptoms: affective, somatic, cognitive

Question 32

affective symptoms of nicotine withdrawal

Answer 32

``` anxiety irritability depressed mood anhedonia (no longer find joy in things) insomnia restlessness hyperaglesia (inc pain response) ```

Question 33

somatic symptoms of nicotine withdrawal

Answer 33

``` tremors bradycardia nausea respiratory changes hunger and weight gain ```

Question 34

cognitive symptoms of nicotine withdrawal

Answer 34

``` difficulty concentrating (attention issues) impaired memory -changes in activation of frontal lobe ```

Question 35

when do symptoms of abstinence syndrome subside

Answer 35

first few days is the worst, goes away within 2-4 weeks

Question 36

what prevents withdrawal symptoms of nicotine

Answer 36

use of nicotine gum, transdermal patches, losenges give low doses so you do not get a rush or reward

Question 37

abstinence syndrome is mediated by a combination of... (4 things)

Answer 37

1. resensitization of the desensitized and up-regulated nAChRs (remove depolarization blocks) 2. reduced activity of mesolimbic dopamine pathway 3. increased CRF in amygdala (antireward system) 4. activation of pathway between medial habenula and interpeduncular nucleus (nicotine aversion/side effects)

Question 38

why do people smoke?

Answer 38

development and maintaining vaping and smoking habits - to deliver nicotine to the body - to keep taking it to maintain steady state

Question 39

secondary reinforcers

Answer 39

conditioned stimuli signal reward is coming ex: that blue hoodie you always smoke in

Question 40

nicotine resource model

Answer 40

smokers routinely report smoking causes relaxation, alleviation of stress, increased ability to concentrate

Question 41

deprivation reversal model

Answer 41

positive effects of smoking represent alleviation of irritability, stress, poor concentration experienced by smokers between cigarettes

Question 42

the "relaxing" effect of smoking almost brings the smoker to the ______ as a typical nonsmoker

Answer 42

same state | homeostasis

Question 43

epigenetics of smoking

Answer 43

- when you are a chronic smoker, changes in over 1000 genes - if parents smoked this could impact your gene expression: memory, mood, how rewarding a drug is, birth defects, and immune system changes - the environment changes what genes are active

Question 44

smoking in pregnancy

Answer 44

- can pass through placental barrier - can effect fetus and brain long lasting deleterious effects on somatic (motor, autonomic, social interactions), and neural behavior development -dec in birth weight, dec in IQ, heart issues

Question 45

adolescent smoking effects the...

Answer 45

PFC!!!! - attention defecits, impulsivity, inc self administration of abused drugs underdeveloped PFC until 25