Class Notes (837,001)
Canada (509,985)
Physiology (903)
PHGY 313 (80)
Lecture

lec 14.docx

2 Pages
105 Views
Unlock Document

Department
Physiology
Course
PHGY 313
Professor
Sebastien Breau
Semester
Fall

Description
The Basic Structure of Transmitter-Gated Channels  Four different types of polypeptides are used as subunits for the nicotinic receptor, and they are designated as: β, α, δ, and γ.  A complete mature channel is made from two α subunits, and one each of β, δ and γ.  There is one ACh binding site on each of the α subunits; the simultaneous binding of ACh to both sites is required for the channel to open  The structure of glutamate receptors resembles that of potassium channels, and this has inspired the surprising hypothesis that glutamate receptors and potassium channels evolved from a common ancestral ion channel Amino Acid-Gated Channels  Amino acid-gated channels mediate most of the fast synaptic transmission in the CNS  Several properties of these channels distinguish them from one another: o Pharmacology of their binding sites describes which transmitters affect them and how drugs interact with them o Kinetics of the transmitter binding process and channel gating determine the duration of their eff2+t o Selectivity of the ion channels determines whether they produce excitation or inhibition and whether Ca enters the cell in significant amounts o Conductance of open channels helps determine the magnitude of their effects Glutamate-Gated Channels:  3 Glutamate Receptor Subtypes: AMPA, NMDA, and Kainate  AMPA-gated and NMDA-gated channels mediate the bulk of fast excitatory synaptic transmission in the brain  AMPA-gated channels are permeable to both sodium and potassium but not calcium  AMPA channels can be activated by a rapid increase in sodium ions into the cell, thus depolarizing the cells  AMPA receptors coexist with NMDA receptors at many synapses in the brain, so most glutamate-mediated EPSPs have components contributed by both  NMDA-gated channels also cause excitation of a cell by admitting sodium, but they differ from AMPA receptors in two very important ways: o NMDA-gated channels are permeable to calcium o Inward ionic current through NMDA-gated channels is voltage dependent  If excessive amounts of calcium are released, it can trigger the death of a cell  Activation of NMDA receptors can cause widespread and lasting changes in the postsynaptic neuron  Inward ionic current through the NMDA channel is voltage dependent G-Protein-Coupled Receptors and Effectors  Transmission at the G-protein-coupled receptors involves 3 steps: o Binding of the neurotransmitter to the receptor protein o Activation of G-proteins o Activation of effector systems The Basic Structure of G-Protein-Coupled Receptors  Most G-protein-coupled receptors are simple variations on a common plan, consisting of a single polypeptide containing seven membrane-spanning alpha h
More Less

Related notes for PHGY 313

Log In


OR

Join OneClass

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

Sign up

Join to view


OR

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.


Submit