PSY EXAM 2.3 - Dopamine

brainstem, striatum, limbic system

Dopamine is released from the __ into the __ and ___ ___

monoamine

Dopamine is considered a ___

transporter

Dopamine is removed from the synaptic cleft by the dopamine ___

Tyrosine, DOPA, Dopamine

Synthesis pathway for Dopamine:

___---->______--->______

norepinephrine

Dopamine can be converted to ___ by DBH

classical, catecholamine

Dopamine is a ___ neurotransmitter and a ___

tyrosine

dopamine, norepinephrine, epinephrine are all synthesized from ___

Tyrosine hydroxylase

___ ____ converts tyrosine into DOPA

Aromatic Amino Acid Decarboxylase (AADC)

_____ converts DOPA --> Dopamine

Vesicular monoamine transporter (VMAT2)

Dopamine is stored in vesicles via ____

2, 1

VMAT__ is primarily in the brain and VMAT___ is in the adrenal medulla (for epinephrine)

Reserpine

___ is a drug that blocks VMAT2

reserpine

___ depletes dopamine by preventing vesicular storage and leading to enzymatic breakdown inside the neuron

autoreceptors (D2 receptors)

Dopamine release is influenced by dopamine ____, which provide negative feedback

tonic, burst

Dopamine neurons can fire in a ____or a ___ pattern

rate

___ of firing helps determine and regulate NT release

5

There are ___ subtypes of dopamine receptors

1, 5

D __ and __ receptors are excitatory, coupled to Gs and stimulate adenylate cyclase

2, 3, 4

D __, ___, ___ are inhibitory and are coupled to Gi, which inhibits adenylate cyclase

no

Are D1 and D2 expressed in the same neurons?

Dopamine transporter (DAT)

__ ___ reuptakes dopamine into neurons

Monoamine Oxidase (MAO)

Inside the neuron, dopamine is broken down by ___ ___, which recycles precursors

COMT

Inside the neuron, dopamine is broken down by ______. which is found mainly in glial and nearby cells especially in the cortex

region

DAT expression varies by brain ___

High (rapid dopamine removal)

Striatum has ___ DAT

Low (dopamine diffuses and is inactivated by COMT)

Cortex has ___ DAT

COMT

___ is more important in cortical dopamine regulation and cognitive functions

motivation

Dopamine's functions can be summed up in one word: _____

VTA, substantia nigra

Dopamine neurons are located in the midbrain in 2 main brain regions: the __ and the __ __

A9

Substantia Nigra is cell group ___

A10, anterior

VTA is cell group ___

Both A9 and A10 project ____ toward the front of the brain

-

Nigrostriatal

The __ pathway: A9, substantia nigra, projects to the dorsal striatum and is important for initiating actions and learning sequences of movemnts

Mesolimbic

The ___ pathway: A10, VTA

- Projects to limbic regions like the nucleus accumbens

- Plays a role in emotional and cognitive aspects of dopamine function

Mesocortical

The __ pathway: A10, VTA

- Projects to the cortex and hippocampus

- Involved in emotional and cognitive functions of dopamine

asymmetry

Lesions with 6-hydroxydopamine (6-OHDA) leads to circling behavior due to ___

VMAT

Re-serpine experiments (1960s): blocks ____ and depletes dopamine

- Results in severe behavioral inactivity, similar to symptoms in Parkinson's disease

synthesis

Dopamine-deficient mouse model:

- Lacking tyrosine hydroxylase, preventing dopamine ____

- Mice exhibit severe behavioral deficits and fail to eat or drink

-Motor capacity was intact and animals still found sweet to be pleasureable, proving DA is not necessary for movement or pleasure

Parkinson's

Neurodegenerative disorder in which dopamine producing neurons in the substantia nigra are damaged and die over time - lead to motor problems and mental disabilities

basal ganglia

The ___ ____ inhibits unwanted motor activity

Lewy

___ bodies start to form in the brains of people with Parkinson's

cocaine

____ blocks the dopamine transporter (DAT) so that it cannot be removed from the synapse

reuptake

cocaine blocks dopamine ___ by blocking DAT, leading to dopamine buildup

overstimulation

excess dopamine causes ___ of postsynaptic receptors

do not

Genetically engineered mice with a cocaine-insensitive dopamine transporter (DAT Knockin) (do/donot) self-administer cocaine.

norepinephrine, serotonin

In addition to DA, cocaine also binds to ___ and ____ transporters and this may ENHANCE Da signaling

glutamatergic

Cocaine increases norepinephrine levels, which stimulates ___ neurons in the prefrontal cortexwhich then project back to VTA enhancing dopamine

Amphetamine

___ targets the DA transporter and enters the presynaptic cell and forces vesicles to release dopamine

reverses

Amphetamine ___ the function of a dopamine transporter and makes it pump out DA instead of take it in

euphoria, motivation

Cocaine produces a feeling of ___ and increased ____

tolerance

Chronic cocaine use leads to ___

fewer/less

Chronic cocaine users have ___ dopamine receptors than non-users