Textbook Notes (362,880)
Canada (158,081)
Psychology (3,261)
PSYC 2410 (149)

Synaptic Transmission.docx

8 Pages
Unlock Document

University of Guelph
PSYC 2410
Elena Choleris

Synaptic Transmission 10/9/2012 6:57:00 AM Synaptic Transmission  Transmission of signal from one neuron to another Types of Synapses:  Axodendritic synapses: axon  dendrites o One way, very common  Axosomatic synapses: axon  cell body (soma) o One way  Dendrodendritic synapses: dendrite  dendrite o Two way, often electrical as opposed to chemical  Axoaxonal synapses: axon  axon o Presynaptic signal modification  Can selectively influence one particular synapse rather than the entire neuron like EPSPs or IPSPs o Rare Electrical Synapses:  Chemical synapses: 5 miliseconds (because diffusion takes place and chemicals have to bind to receptors) o Glial cells  Astrocytes have been shown to release chemical transmitters to contain receptors for neurotransmitters to conduct signals and to participate in neurotransmitter reuptake  Electrical synapses: faster  Why don’t we just have electrical synapses? o Limited, only excitatory and only 1 electrical signal o Membrane coupling o Direct transmission  Vs. indirect transmission in which neurotransmitter is released from series of varicosities along axon (aka string of beads)  More common in invertebrates, mammals  Properties: o Gap junctions (allows membrane coupling)  Sets of channels  6 connexins  1 connexon  2 connexons (one on either cell)  1 gap junction o Free movement (of small molecules and ions between cells) o Passive spread (of depolarization) therefore very fast o Bidirectional  Functions: o Neuron – neuron inhibitory circuits o Neuron – glial cells (astrocytes and communication with other cells) o Functionally interact Neurotransmitters 10/9/2012 6:57:00 AM Neurotransmitters  Many neurons synthesize and release one neurotransmitter o But there is often coexistence between multiple transmitters  Synthesis: in the cell body o Bigger neuropeptides/proteins: somal vesicle packaging  Active axoplasmatic transport (~40 cm/day) via cytoskeleton o Small molecules: axonal travel (usually passive along concentration gradient) are not packaged until reaching the terminal buttons by Golgi complex  Directed, Cell A  cell B  Non directed, release neurotransmitters into general area Release of Neurotransmitters:  Action potential reaches the synaptic terminal  Voltage-activated calcium (Ca2+) channels open  Ca2+ ions influx into terminal button  Causes presynaptic vesicles to fuse (dock, by SNARE proteins on vesicle membrane) with the cell membrane  Release of neurotransmitter in the synaptic cleft (synapse) o “Exocytosis”  Kiss and run  not all neurotransmitters are released, vesicle retracts back into cytoplasm Receptor Activation:  Receptor: a protein that contains the binding site for a specific neurotransmitter (ligand) o Lock and key analogy (key neurotransmitter, needs to be specific) o Puzzle piece analogy (any one receptor has many binding sites  Differences in affinity between receptors for a neurotransmitter  Receptor subtypes: e.g. dopamine has 5 receptor subtypes (D1, D2 …
More Less

Related notes for PSYC 2410

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.