Wk 3 BB Flashcards
Drug effects
The changes a drug produces in an animal’s physiological
processes and behavior. In the nervous system, most drugs affect
synaptic transmission.
Antagonist
A drug that opposes 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.
sites of action
location where molecules of drugs interact woth molecules on or in cells of the body, thus affecting some biochemical processes of these cells
main sites of action of drugs
- Production of neurotransmitters
- Storage and release of neurotransmitters
- Effects on receptors
- Effects on reuptake
Direct agonist/antagonist
A drug that binds with and activates a
receptor. This drug mimics the effects
of a neurotransmitter
Indirect agonist/antagonist
A drug that attaches to a binding site
on a receptor and facilitates the action
of the receptor; does not interfere with
the binding site of the principal
neurotransmitter.
Both types of drugs prolong the presence of the neurotransmitter in the
synaptic cleft (and hence in a location where they can stimulate
postsynaptic receptors), they serve as_____
agonists.
In the brain most synaptic communication is accomplished by two neurotransmitters:
- with excitatory effects (glutamate)- the driving force of the brain
- with inhibitory effects (GABA or glycine - spinal cord) - The breaks of the brain
Nocebo Effect
People can feel worse after an intervention
that should have no ill effects
Acetylcholine - ACh
The primary neurotransmitter secreted by the efferent axons of the CNS
All muscular movement is accomplished by the release of acetylcholine
ACh is involved in regulating REM sleep - dreaming (doroslateral pons),
perceptual learning (forebrain), and memory (hippocampus).
ACh receptors: nicotinic and muscarinic
ACh found at the target of parasympathetic branch of the ANS – outside of the CNS,
first discovered neurotransmitter – the importance of Otto Loewi
The effects of ACh are generally facilitatory
Cholinergic Synapses
Synapses that have acetylcholine
transmitter are called cholinergic
synapses.
Nicotinic receptor
UNDERSTAND MORE
an ionotropic acetylcholine receptor
stimulated by nicotine
stimulated by nicotine and blocked by curare (paralysis).
Muscarinic receptor
stimulated and blocked by what
a metabotropic acetylcholine
receptor
stimulated by muscarine and blocked by atropine.
Atropine acts by …
preventing acetylcholine from
depolarising the post-synaptic membrane and
increases heart rate
… are four neurotransmitters
that belong to a family of compounds called monoamines.
Because the molecular structures of these substances are similar, some drugs
affect the activity of all of them to some degree
Dopamine, norepinephrine, epinephrine, and serotonin
Dopamine
The reward pathway and addiction
Natural rewards: food, water, sex, nurturing
Addiction: a state in which an organism engages in compulsive behaviour,
behaviour is reinforcing (rewarding, pleasurable), loss of control for limiting intake
Tolerance
A state in which organism no
longer responds to a drug
* A higher dose is required to
achieve the same effect
Dependence
A state in which organism
functions normally only in the
presence of a drug
* Manifested as physical
disturbance when the drug is
withdrawn
_______ circuits in the brain: it is _______
to be dependent on the morphine,
without being addicted to it.
Different
possible
Acetylcholine action (+ or -) and receptors
+/-
Nicotinic, Muscarinic
Nigrostriatal system
starts in the substantia nigra
and terminates in the basal
ganglia : plays a role in the
control of movement.
Dopamine is indeed involved in addiction, but it is not only a “pleasure chemical”.
Dopamine is involved in many brain functions – everything from
regulating movement to
control of attention
Serotonin
- also called 5-HT
- Influences regulation of mood, control of eating, sleep, dreaming and arousal
- involved in regulation of pain.
Serotonin is involved in the control of:
1. 2,3,4,5,6,7,8
- appetite
- sleep
- memory and learning
- temperature regulation
- cardiovascular function
- muscle contraction
- endocrine regulation
- depression
Norepinephrine
/noradrenaline
Norepinephrine (NE) or noradrenaline is both a hormone and a
neurotransmitter.
- As a hormone, secreted by the adrenal gland, it works alongside
epinephrine/ adrenaline to give the body sudden energy in times of stress,
known as the “fight or flight” response.
Medications that inhibit reuptake of NE can effectively treat depression. In
addition, elevated NE are found in patients experiencing mania
Epinephrine (adrenaline) is a hormone secreted by the adrenal medulla;
serves as a neurotransmitter in the brain.
GABA is used at the great majority of fast _______synapses in virtually every part of the brain.
Many sedative/tranquilizing drugs act by enhancing the effects
of ______. Correspondingly glycine is the inhibitory transmitter in the spinal cord.
inhibitory
GABA
Glutamate is used at the great majority of fast __________synapses in the brain and spinal cord.
It is also used at most synapses that are “________”, i.e.
capable of increasing or decreasing in strength.
Modifiable synapses are thought to be the main memory-storage elements in the brain
excitatory
modifiable
