Last Lecture Flashcards
(34 cards)
What is the mesolimbic pathway?
- dopaminergic neurons in the ventral tegmental area project to the nucleus accumbens, prefrontal cortex, olfactory tubercle, amygdala
Dopamin ____ is in turn _____ by nicotinic acetylcholine receptors. What is this important to?
- modulation
- modulated
- indirect path
What symptom is Parkinson’s can nicotine reduce?
dyskinesia
What extinguishes nicotine self-administration?
- 6-OH dopamine lesions of dopaminergic terminals in the nucleus accumbens
What receptors are responsible for nicotinic addiction?
- alpha4 nAChRs
Which pathways/areas contribute to nicotinic addiction?
- mesolimbic dopaminergic pathway
- anterior cingulate cortex and hippocampus
- lateral septum ventral and amygdala
- lateral hypothalamic area and paraventricular and arcuate nuclei
- hypothalamic-pit-aden axis and hippocampus and frontal cortex
What symptom of nicotinic addiction does the mesolimbic dopaminergic pathway cause?
- pleasure and relieve craving
What symptom of nicotinic addiction does the anterior cingulate cortex and hippocamppus cause?
- improvement in cognitive function, attention, learning and memory
What symptom of nicotinic addiction does the lateral septum ventral and amygdala cause?
- reduction in stress and anxiety
What symptom of nicotinic addiction does the lateral hypothalamic area, paraventricular and arcuate nuclei cause?
- decrease appetite
What symptom of nicotinic addiction does the hyothalamic-pit-aden axis, hippocampus, and frontal cortex cause?
- relieve depression
What other factor is also involved in nicotinic addication?
- social pressures
What does chronic nicotine intake result in in terms of modulation?
- upregulates nicotine binding
- more nAChR receptors in many brain areas
In what areas do we see a significant increase in alpha4 nAChR expression?
- VTA (TH+) DA (NS)
- VTA (GAD+) GABA
- SNC (TH+) DA (NS)
- SNR (GAD+) GABA
- Nucleus accumbens (NS)
- proportionality GABA increases more
We see a shift in the intensity of GABAergic neurons with nicotine use, what does this indicate?
- chronic nicotine increases alpa4 receptors in GABAergic and not dopaminergic neurons
What is increased by chronic nicotine?
- increases firing rates of GABAergic midbrain neurons
- increases basal firing and response to nicotine
What is decreased by chronic nicotine?
- decreases firing rates of dopaminergic midbrain neurons
- decreases basal firing and response to nicotine
What does the circuit based mechanism of tolerance of reward tell us?
- GABAergic to dopaminergic
- saline and first use: greater firing in dopaminergic for anticipation and reward
- chronic nicotine: more firing in GABAergic for anticipation (craving) and reward (decreased reward)
What does chronic nicotine exposure cause in the ventral tegmentum?
- upregulates nACh receptors on GABAergic neurons
- no effect on nAChR levels in dopaminergic neurons
What does the effect of chronic nicotine exposure on the ventral tegmentum cause?
- lower basal dopamine release
- suppression of dopamine release when exposed to acute nicotine
Why might you see dopamine release increase during exposure to acute nicotine?
- increases only to reach or slightly exceed the levels that normally exist as basal levels in naive animals
Why do both nicotine and cocaine cause addictions?
- they use the same pathway
- craving and tolerance result
- different places in pathway that drug has effect
Where does nicotine have it’s effect in DA neurons and GABA interneurons?
- GABA and dopamine neurons
- at glutamate inputs to dopaminergic neurons of VTA and nucleus accumbens?
Where does cocaine have it’s effect?
- at synapse of dopaminergic neurons
