2010
Question 1. Classify and characterize various types of memories. What brain regions are
responsible for their acquisition?
Classify and characterize various types of memories. What brain regions are responsible for
their acquisition?
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1. Declarative (explicit) o Semantic (facts) – hippocampuso Events (events) -
hippocampus, amygdala
2. Nondeclarative (implicit)o Procedural(skillsandhabits)-cerebellumo
Priming(neocortex)o Classicalconditioning(hippocampus,amygdala,cerebellum)
3. Non-associative learning – reflex pathways
4.
Question 3. Describe the approaches used to determine (i) the localization of P2X
receptors in the body, (ii) which P2X receptors can form heteromeric channels and (iii)
whether P2X receptors interact with other receptors/proteins?
(i) determine the localization of P2X receptors in the body
Use of the amino acid sequence of the seven P2X receptor subunits can be used to map
localization. This can be done at the level of mRNA through Northern blotting (will show
what tissues can be expressed in but not detail on which cell types within the tissue). Can
use the sequence to design oligos for in situ hybridization that should give localization to
particular cell types within a tissue but still only looking at mRNA . Use of the amino acid
sequence to generate selective antibody for the receptor that can be used for
immunohistochemistry – advantages that will give cellular distribution. May also suggest
that could deveop knock-in mice with tagged P2X receptors.
Could also characterize P2X receptor properties of a particular tissue and compare to
properties of recombinant receptors.
(ii) which P2X receptors can form heteromeric channels
Approaches rely on co-expression of P2X receptor subunits. One approach is to look for
novel phenotype on expression of different subunits – were given the example of P2X2 and
P2X3 co-expression to give channels with the time course of P2X2 and the pharmacology of
P2X3. More general approach is to co-express the proteins and look to see whether they can
co-immunoprecipitate. Would need to give some information here on how to do an IP and
appropriate controls.
(iii) whether P2X receptors interact with other receptors/proteins?
Two examples that could be used here. (1) Interaction of P2X and nicotinic receptors – lack
of addition of the currents when co-stimulated, P2X blocks the nicotinic component and (2)
Use o f immunoprecipitation and mass spectrometry to identify interacting proteins. The
example given was of the P2X7 receptor.
The aim for this question is for the student to think about and demonstrate their
understanding of the methods/approaches that can be used to characterize receptors.
