Neurotransmitters Flashcards
what neurotransmitters accomplish most communication in the brain?
glutamate (with excitatory effects)
GABA or glycine -spinal cord (with inhibitory effects
what do effects do all neurotransmitters other than glutamate and GABA have?
modulating effects
tend to activate or inhibit entire circuits of neurons that are involved in particular brain functions
psychopharmacology
the study of the effects of drugs on the nervous system and behaviour
drug effects
the changes a drug produces in an animal’s physiological processes and behaviour
what do most drugs effect in the nervous system?
synaptic transmission
antagonist
a drug that opposed or inhibits the effects of a particular neurotransmitter on the postsynaptic cell
agonist
a drug that facilitates the effects of a particular neurotransmitter on the postsynaptic cell
acetylcholine
the primary neurotransmitter secreted by the efferent axons of the CNS
what neurotransmitter is all muscular movement accomplished by?
acetylcholine
what is ACh involved in
regulating REM sleep- dreaming (doroslateral pons), perceptual learning (basal forebrain) and memory (hippocampus)
where is ACh found?
at the target of parasympathetic branch of the autonomic nervous system
what are the general effect of ACh
facilitatory
ACh receptors
nicotinic and muscarinic
nicotinic receptor
an ionotropic acetylcholine receptor stimulated by nicotine
where are nicotinic receptors found?
post synaptic membrane of:
- all autonomic ganglia
- All neuromuscular junctions
- some CNS pathways
what happens when a nicotinic receptor is bound
depolarisation, influx sodium and outflux potassium, excitation
muscarinic receptor
a metabotropic acetylcholine receptor
what type of receptor is a muscarinic receptor?
G protein coupled receptors
what effects does binding of a muscarinic receptor produce?
parasympathetic nerve effects in the heart, smooth muscles and glands
effects at muscarinic receptors (excitatory of inhibitory)
hyperpolarisation, K+ channels open = inhibition
depolarisation, K+ channels close = excitation
what are nicotinic receptors blocked by?
curare
what does curare do?
act as the junction between nerve cells and muscles causing paralysis
how does atropine act?
by preventing acetylcholine from depolarising the post-synaptic membrane in the parasympathetic branch
what is atropine a treatment for?
low heart rate
botulinum toxin
acetylcholine antagonist, prevents release by terminal buttons
black widow spider venom
a poison produced by the black widow spider that triggers the release of acetylcholine causing convulsions (agonist)
the monoamines
dopamine
norepinephrine
epinephrine
serotonin
why do some drugs effect the activity of all monoamines?
because the molecular structures of the substances is similar
natural awards
food, water, sex, nurturing
addiction
a state in which an organism engages in compulsive behaviour, behaviour is reinforcing, loss of control for intake
addiction
a state in which an organism engages in compulsive behaviour, behaviour is reinforcing, loss of control for intake
tolerance
a state in which an organism no longer responds to a drug, a higher does is needed to exert the same effect
dependence
a state in which an organism functions normally on the presence of a drug
manifested as a physical disturbance when the drug is withdrawn
can you be dependent without being addicted?
yes, they are different circuits in the brain
cocaine
cocaine inhibits dopamine reuptake in the dopaminergic synapse in nucleus accumbens, leading to increased activity of the reward system
cocaine effect on metabolic activity
glucose reduction
nigrostratial system
starts in the substantia ganglia, terminates in the basal ganglia
plays a role in the control of movement
parkinson’s disease
neurological condition caused by degeneration of the nigrostratial system
what has parkinsons’s disease been treated with?
L-DOPA
what is Parkinson’s disease characterised by?
tremors
rigidity of the limbs
poor balance
difficulty initiating movements
what is serotonin also called
5-HT
What does serotonin play a role in?
regulation of mood, behaviour, endocrine system and pain
control of eating, sleep, dreaming, memory, learning, temp regulation, cardiovascular function, muscle contraction and arousal
LSD
stimulates centres of the sympathetic nervous system in the midbrain leading to:
pupillary dilation, increase in body temperature, increase in blood sugar levels
MDMA
a drug that serves as a serotonergic agonist, has excitatory and hallucinogenic effects
effects of MDMA of serotonin transporters
prevent reuptake
work in reverse mode, bring more 5-HT into the synapse
acute effects of ecstasy
heightened perceptions
reduced appetite
elevated mood
stimulation
adverse effects of ecstasy
depression-like feelings irritability clouded thinking hyperthermia disturbed behaviour jaw clenching
long term effects of serotonin
neurotoxicity- serotonin levels decreased from before after taking ecstasy
impairments of verbal and visual memory
what is believed to be the cause of many cases of mild- severe depression? what symptoms can this lead to?
low serotonin levels
symptoms: anxiety, apathy, fear, feelings of worthlessness, insomnia and fatigue
antidepressants
medications that increase the amount of serotonin levels at the synapse by blocking the reuptake of serotonin into the presynaptic cell
medications that inhibit the reuptake of norepinephrine
can be effective in patients with depression
elevated levels of ….. found in patients experiencing mania
norepinephrine
norepinephrine
neurotransmitter and hormone
as a hormone, secreted by the adrenal gland, it works along side epinephrine to give the body sudden energy in times of stress
most common neurotransmitters in the CNS
glutamate, gamma-aminobutyric acid (GABA), glycine
glutamate
an amino acid, most important excitatory neurotransmitter in the brain
NMDA receptor
specialised ionotropic glutamate receptor
PCP (angel dust)
synthetic drug
indirect antagonist of NMDA receptors
imbalances in GABA neurotransmitter are linked to
bipolar disorder, schizophrenia and anxiety disorder
most important inhibitory neurotransmitter in the brain
GABA
most important inhibitory neurotransmitter in the spinal cord
glycine
GABA is a part of the brain system that allows us to:
fine tune our moods, thoughts and actions with an incredible level of detail
what does GABA provide?
necessary inhibitory effect that we need in order to block out excessive brain activity that in depression may lead to negative thinking
Benzodiazepine
tranquilizer
a category of anxiolytic drugs: an indirect agonist for the GABA A receptor
e.g. valium (diazepam)
