substrates Flashcards
what are the 4 catecholamines
- dopamine
- noradrenaline
- serotonin
- acetylcholine
what are catecholamines
neurotransmitters and hormones derived from the amino acid tyrosine
- they play a key role in the body’s stress response, regulation of blood pressure, heart rate and various metabolic processes
what does cocaine do to neurotransmitters
- inhibits DA and NA transporters
what does amphetamines do to neurotransmitters
increased DA and NA release
what does risperidone do to neurotransmitters
blocks DA receptors
what does Ritalin do to neurotransmitters
blocks DA and NA uptake
what is Reserpine and what does it do
- general catecholamine antagonist
- inhibits VMAT - a protein responsible for moving them back into vesicles
what did Bloomfield et al 2016 and Reigal ate al 2007 find about indirect antagonists
THC promotes DA release through cannabinoid receptors
- long term DA system dulling
what are dopamine pathways
neural circuits through which dopamine travels to regulate various physical and psychological functions
- these pathways are critical for processes like movement, reward, motivation, emotion and hormonal control
what are the four dopamine pathways
- mesocortical
- mesolimbic
- nigrostriatal
- tuberoinfundibular
where does the mesocortical originate
in the ventral tegmental area but projects to the prefrontal cortex
what does mesocortical do
regulates cognition, decision making, emotion and social behaviour
what is underactivity in the mesocortical pathway associated with
negative symptoms of schizophrenia and cognitive impairments
what do drugs that target the mesocortical pathway aim to do
aim to modulate dopamine activity in the prefrontal cortex
what do mesocortical drugs address
- cognitive dysfunction, emotional regulation, and negative systems in disorders like schizophrenia, ADHD and depression
what is the function of the mesolimbic dopamine pathway
involved in reward, motivation and the feeling of pleasure
where does the mesolimbic pathway originate
in the ventral tegmental area and projects to the nucleus accumbens and other limbic areas
what does overactivity in the mesolimbic pathway do
linked to addiction, positive symptoms of schizophrenia and other disorders involving reward processing
what do drugs that target the mesolimbic pathway aim to do
modulate the dopamine activity in the reward and motivation system of the brain
what are mesolimbic drugs used to treat
- schizophrenia
- addiction
- depression
- parkinson’s disease
what does high dopamine in the mesolimbic pathway result in
psychosis, addiction, mania
what does low dopamine in the mesolimbic pathway result in
depression, anhedonia, apathy
what does the dopamine pathway nigrostriatal do
controls movement and motor planning by facilitating the interaction between the basal ganglia and other motor control systems
where does nigrostriatal pathway originate
starts in the substania nigra and projects to the striatum
what happens if there is degeneration of neurons in the nigrostriatal pathway
- a hallmark of parkinson’s disease, leading to tremors, rigidity, and bradykinesia
what happens if there is overactivity in the nigrostriatal pathway
- involuntary movements like tardive dyskinesia
what are nigrostriatal drugs crucial for
motor control
what are nigrostriatal drugs used for
parkinson’s disease, drug-induced movement disorders, and Huntington’s disease
what does low dopamine in the nigrostriatal pathway do
leads to parkinson’s disease
what does excess dopamine in the nigrostriatal pathway do
leads to tardive dyskinesia and huntington’s chorea
what does the dopamine pathway tuberoinfundibular do
regulates the secretion of prolactin from the anterior pituitary gland, playing a role in hormonal control
where does the tuberoinfundibular pathway originate
the hypothalamus and projects to the pituitary gland
what can dysfunction in the tuberoinfundibular pathway do
can result in hyperprolactinemia, leading to symptoms such as infertility, sexual dysfunction and galactorrhea
what does dopamine act as in tuberoinfundibular drugs
a prolactin antagonist
what does decreased prolactin in the tuberoinfundibular pathway lead to
hypopituitarism
what does increased prolactin in the tuberoinfundibular do
lead to infertility, menstrual irregularities, decreased libido, and galactorrhoea
what receptors does DA have
- D1-like (D1, D5)
- D2 - like (D2, D3, D4)
which DA receptor activates easily
D3
which DA receptor is not activated easily
D1
which DA receptor excites the neuron
D1-like
which DA receptor calms down the neuron
D2-like
what did Giros et al 1996 find
an animal under treatment to become more hyperactive will respond by wanting more of that treatment, suggesting it’s rewarding and showing addicting potential
what did Xu, Guo, Vorhees and Zhang 2000 find
mutant mice lacking D1 receptors are insensitive to cocaine which increased locomotor activity in the wild-type but not the knockout mice
