Midterm 2 Flashcards
(140 cards)
what are the indolamines?
serotonin, melatonin
what enzyme converts DOPA to dopamine?
aromatic amino acid decarboxylase
what enzyme converts dopamine to norepinephrine?
dopamine beta-hydroxylase
tyrosine hydroxylase activity is regulated by:
- high catecholamine levels (negative feedback)
- increased cell firing rate stimulates TH (increased synthesis of catecholamines)
what is a monoamine-specific transporter involved in vesicle packaging?
vesicular monoamine transporter (VMAT)
what drug blocks vesicular monoamine transporters?
Reserpine
what drugs induce synaptic vesicle release without cell firing?
amphetamine and methamphetamine (causes release of DA)
mesostriatal (nigrostriatal) pathway
from substantia nigra (A9) to striatum (caudate and putamen), facilitates voluntary movement
mesolimbocortical
from ventral tegmental area (A10) to limbic system and prefrontal cortex, reward pathway, implicated in schizophrenia
what are 3 brain regions where norepinephrine is produced?
locus coeruleus (pons) (A6), lateral tegmental area, dorsal medullary group
where does norepinephrine neurons project to?
forebrain, cerebellum, spinal cord, made in the vesicle
what are locus coeruleus (LC) connections to medial septum and medial preoptic areas involved in?
wake
what are LC connections to PFC involved in?
attention and working memory
what are the dopamine receptor subtypes?
ALL METABOTROPIC
- D1-like (stimulate adenylyl cyclase and synthesis of cAMP): D1 and D5
- D2-like (inhibit adenylyl cyclase and cAMP): D2, D3, D4
- autoreceptor = D2 (activate a G protein that enhances potassium channel opening - GIRK)
DA transporter KO
extremely hyperactive, do not respond to psychostimulants
D1 receptor KO
deficits in several cognitive tasks
D2 receptor KO
impairment in spontaneous movement, coordination, and posture control
D1/D2 double KO
fatality during 2nd or 3rd week of life
NE adrenergic receptor
ALL METABOTROPIC 2 types: -alpha 1: phosphoinsotide -alpha 2: reduce synthesis of cAMP = Gi -beta 1 and beta 2: stimulate adenylyl cyclase and enhance synthesis of cAMP, G2 -autoreceptor = alpha 2
agonists of alpha 2 receptors in PFC:
enhance working memory
agonists of alpha 1 receptors in PFC:
deleterious effect on cognitive functions, increased activation with stress to produce cognitive impairment
antagonists of beta-1 receptors (beta blockers)
generalized anxiety disorder
what are transporter-blocking drugs of catecholamines?
- tricyclic antidepressants (inhibit uptake of NE and 5-HT)
- antidepressant reboxetine and ADHD drug atomoxetine block NE transporters
- cocaine blocks reuptake of all monoamines (DA, NE, 5-HT)
how are catecholamines inactivated?
-reuptake by transporters (repackaged into vesicles or broken down)