Test 2 Flashcards
Dendritic Spine
a small bud on the surface of a dentrite that the terminal button of another neuron attaches to making a synapse
Presynaptic membrane and postsyanptic membrane
presynaptic membrane is located on the terminal button and faces the postsynaptic membrane which is located on the neuron recieving the message
Synaptic Cleft
the gap between the pre and post synaptic membranes of two neurons
3 types of synapses
- Axondendritic synapes; occur on smooth surface of dendrite and on dendrite spine (both with termnial button)
- Axsomatic synapses: occur on the somatic membrane with termnial button
- Axoaxonic synapses: occur between two termnial buttons
1 and 2 effect postsynapse (either postsynaptic facilitation or postsynaptic inhibitiation)
Two Types of Receptors for Synapses
Direct and Indirect
1. Ionotropic receptor: is direct; neurotransmitters talk with this receptor which has a binding site for the NT’s and a ion channel. The channel opens when the NT’s connect with the neurons binding site; THIS IS FAST AND DIRECT
2. Metabotropic Receptor: Indirect; takes longer but lasts longer; needs metabolic energy to open ion channel; is a receptor within a neuron that when connected with a molecule of an NT it produces a second messenger which then opens the ion channel
This receptor is located closely to G-proteins which is activated when molecule of NT connects with receptor and creates an enzyme that creates the second messenger.
G-Protein
next to metabotropic receptors that when activated, create a chemical called the second messenger.
Second messenger
a chemical produced by the enzyme in a G-protein. When produced this chemical allows for ion channels to be opened within a neuron
Autoreceptor
self; a receptor molecule on a neuorn that responds to its own the neurotransmitter
IS LIKE A THERMOSTAT, turns off the production and release of neurotransmitters if there are too many; do not produce change in membrane potential because they are not in control of ion channels; REGULATE SYTHESIS AND NEUROTRANSMITTER PRODUCTIONS
Neuromodulator
is like a NT but it is not restricted to the synaptic cleft; but travels through the extracellular fluid; CAN GO FAR
Most are peptides
Peptides
a in neuromodulators and some hormones; is a chain of amino acids joined together by peptide bonds
site of action
place where drugs effect certain molecules within our body and thus cause some biochemical change
Pharmacokinectics
the movement of drugs within the body
Gap Junctions
pruely electrical synapes
more neurons without NT’s
are immediate
not modiable (more reflexsive)
Tolerance
drug becomes less effective; need more and more to get the same resutl
Sensitivity
drug becomes more effective; need less and less to get the same result
Withdrawal
effects when a drug is administered repeatedly and then taken away
Two types of drugs
antagonist: drugs that block or inhibit postsynaptic effects
agonists: drugs that increase or facilitate postsynaptic effects
Effect of Drugs on Production of Neurotransmitters
the synthesis is conotrolled by enzymes; so when drug inactivites one of these enzymes it will prevent the neurotransmitter from being produced; drug serves as an antagoinist
Effect of Drugs on Storage and Release of Neurotransmitters
Drugs act as antagonist is storage of NT’s by binding to transporter molecules which are incharge of filling vesicles with NT’s
Drugs act as antagonist and agonists with the release of NT’s from the terminal button; they deactive or activate proteins that make vesicles fuse with presynaptic membrane and expell them into the synaptic cleft
Effect of Drugs on Receptors
MOST IMPORTANT EFFECT ON NERVOUS SYSTEM BY DRUGS
Postsynpatic Receptors: can be affected by drugs as antagonist or agonists; the drugs attach to the postsynaptic receptor just as NT’s do, which blocks NT’s from connecting. When connected the drug can act as direct antagonist and not allow ion channels to open or it can act as an direct agonist and cause the ion channels to open
OR can be a noncompetitive binding situation in which the same actions occur but NT’s are still allowed to bind to recptors but the Recport is still controlled by drugs being indirect antagonist or indirect agonists
Noncompetitive Binding
when a postsynapic receptor has multiple binding sites and thus the NT’s and other modulators or drugs do not have to compete to bind; receptor becomes either a indirect antagonist or indirect agonist depending on what the drug does