Neurophysiology: Neurotransmission

Neuropharmacology

is the study of drugs that change processes controlled by the nervous system

What do nearly all drugs act on?

alter synaptic transmission

Steps in Synaptic Transmission

Transmitter synthesis- we have to create the transmitter first

Transmitter storage- we don’t always use them right away-stored within the synaptic junction

Transmitter release- stimulation triggers the release of transmitter into synaptic junction

Binding of transmitter to its receptor- does what it needs to do

Termination of transmitter-blockage of reuptake, enzymatic degradation, diffusion

How do drugs impact synaptic transmission?

drugs can impact these five different stages to either increase or decrease the activity

If I reduce storage of a transmitter does that increase or decrease activity?

decreases activity because I have less transmitter available

What are the two major categories of receptors?

Cholinergic and adrenergic

Types of cholinergic receptors?

Nicotinic_N -does not have any real value when talking about pharmacology

Nicotinic_M -contraction of skeletal muscle

Muscarinic -feed and breed & rest and digest (parasympathetic system)

Adrenergic receptor types?

alpha 1-arterioles: skin, viscera, mucous membranes (constriction)

alpha 2-inhibition of transmitter

beta 1-heart and kidney

beta 2- arterioles: heart, lung and skeletal muscle

dopamine- kidney

How many and what neurotransmitters are there that can stimulate the adrenergic receptors?

3 neurotransmitters

epinephrine, norepinephrine, and dopamine

Beta 2 receptors are stimulated by?

Epinephrine

Dopamine receptors are stimulated by?

dopamine

Epinephrine stimulates what receptors?

alpha 1

alpha 2

beta 1

beta 2

Norepinephrine stimulates what receptors?

alpha 1

alpha 2

beta 1

what is acetylcholinesterase?

an enzyme that’s job is to break down acetylcholine and clear it out of the synaptic junction

Dopamine turns into what that gets stored

norepinephrine

what enzymes are responsible for the degradation of norepinephrine?

MAO- monoamine oxidase breakdown into an inactive product

catechol-O methyltransferase- secreted by the liver and kidneys degrades norepinephrine that’s floating around on circulation