Neuron Bathed in Muscimol (GABA agonist) & Baclofen(GABAb agonist)

The figure below is taken from the cerebellum of a rat. Plate 1 shows
the normal activity of a neuron. Plate 2 shows the activity of a
neuron after being bathed in muscimol (a GABAa agonist). Plate 3 shows
the activity of a neuron after being bathed in baclofen (a GABAb
agonist). Plate 4 shows the wash-out of drugs. Explain this figure
(i.e., what is happening at the synapse? Why is one type of GABA
agonist more effective than the other?) Explain how each receptor
functions to affect synaptic activity.

Neurotransmitter receptors come in a variety of shapes and sizes. The
most diverse are the AMPA receptors. First, describe the arrangement of
these receptors (which subtypes are necessary to make up a functional
receptor, which ones are involved, how many possibilities can a typical
receptor have, etc.). Then, tell me what are the possible
electrophysiology and biochemical changes that occur when you mix and
match different subtypes. (8 pts).

What are the advantages to the neuron to have an AMPA receptor with so
many functional variations?

(5 pts).

Would you expect ALL mammalian neurons to have functional NMDA
receptors? Explain your answer. (5 pts)

You’re a famous neurophysiological sitting in the faculty lounge at
Harvard. Suddenly, your graduate student rushes in with a panicked look
in her eye. After you point out to your student that she can be
suspended for being in the faculty lounge without an escort, you ask her
to explain the problem. It seems that she has been recording
intracellularly from the neocortex of a mouse. If she places her
electrode on one set of pyramidal neurons (Layer 2) and adds
fenfluramine (a serotonin uptake blocker), within 5 minutes the neurons
produce a GREATER amount of action potentials. But when she places
fenfluramine while recording from another set of pyramidal cells (Layer
5), these neurons show a DECREASE in APs after 5 minutes of treatment.
Help, she cries! What do you tell her?? Describe how is it possible
for one drug to affect similar cells in completely different methods.
(10 pts)

2 agonist; idazoxan is a 2 antagonist. Using your knowledge on
how post-synapses work, explain the figure. (10 pts).

You have discovered a new chemosensory organ in the crayfish swimmeret.
Describe the experiments that you would perform to identify the
chemicals involved in transduction of the stimulus to nerve impulses
(G-proteins, cAMP, IP3, etc.). (10 pts)

What experiments would you do to identify where the new sense was
processed in the crayfish brain? (5 pts).

You isolate a novel protein from the synapse of a cockroach. Since you
discovered it, you get to name it, calling this protein synaptoroach.
By using immunohistochemistry, you determine that this chemical is found
in axon terminals. Thus, you suspect that it might have something to do
with synaptic release of vesicles. Like all scientist you are poor and
must write grants to make a living. Identify TWO experiments that you
would put into a grant proposal that would prove conclusively that
synaptoroach is essential in synapse physiology. (10 pts)

The latest fad in synaptic physiology is the characterization of
receptor-binding proteins in the post-synapse. These proteins
apparently bind and perhaps localize specific receptors to their proper
synaptic site. Your assignment is to find TWO references in the
neuroscience literature that pertain to two different receptor-binding
proteins involved in this phenomena. Attach the abstract of each
reference to this page (1 point per abstract) and for 3 points each give
a brief summary of each paper (which receptors does it target, where is
it located, etc.).

Reference #1 summary:

Reference #2 summary:

How is it possible to have the ability to detect an almost infinite
number of odors? What mechanisms are involved in how the brain codes
for all these odors? (8 pts)

When Junie Hildebrandt gave her lecture, she talked about many
non-invasive techniques used by neuroscientists to explore how the
living brain functions. Identify THREE techniques that she discussed
and tell me the strengths and weakness/limitations of EACH technique (9
points).