Class Notes (836,289)
Canada (509,725)
Psychology (5,217)
PSYCH 3AB3 (102)
P.Guo (34)
Lecture 14

lecture 14.doc

3 Pages
Unlock Document


Studying Neurotransmitter Systems: • Certain criteria must be met to distinguish a molecule as a neurotransmitter: o The molecule must be synthesized and stored in the presynaptic neuron o The molecule must be released by the presynaptic axon terminal upon stimulation o The molecule must produce a response in the postsynaptic cell Localization of Transmitters and Transmitter-Synthesizing Enzymes: • Hints that a particular molecule may be a neurotransmitter: o Molecule is concentrated in the brain tissue o Application of the molecule to certain neurons alters their action potential firing rate • To confirm the molecule is a neurotransmitter, the molecule must be localized in and synthesized by particular neurons • Two techniques used are immunocytochemistry and in situ hybridization Immunocytochemistry: • Immunocytochemistry- a method used to anatomically localize particular molecules to particular cells o Once the neurotransmitter candidate has been chemically purified, it is injected into the bloodstream of an animal, where it stimulates an immune response o The response is the generation of large proteins called antibodies  Antibodies can bind tightly to specific sites on the foreign molecule such as the transmitter candidate  Best antibodies for this method bind very tightly to the transmitter of interest, and bind very little or not at all to other chemicals in the brain o This method can be used to localize any molecule for which a specific antibody can be generated In Situ Hybridization: • Is also useful for confirming that a cell synthesizes a particular protein or peptide • Recall: proteins are assembled by the ribosomes according to instructions from specific mRNA molecules • A unique mRNA molecule for every polypeptide is synthesized by a neuron • If the sequence of nucleic acids in a strand of mRNA is known, it is possible to construct in the lab a complementary strand that will stick to the mRNA molecule o Complementary strand is called a probe o Process by which the probe bonds to the mRNA molecule is called hybridization • In order to see if the mRNA for a particular peptide is localized in a neuron, we chemically label the appropriate probe so it can be detected, apply it to a section of brain tissue, allow time for the probes to stick to any complementary mRNA strands, then wash away all the extra probes that have not stuck; finally we search for neurons that contain the label • In situ hybridization, probes are usually labelled by making them radioactive o Since we cannot see radioactivity, hybridized probes are detected by laying the brain tissue on a sheet of special film that is sensitive to radioactive emissions o After exposure to the tissue, the film is developed like a photograph, and negative images of the radioactive cells are visible as clusters of small dots  This technique for viewing the distribution of radioactivity is called autoradiography • Immunocytochemistry is a method for viewing the location of specific molecules, including proteins, in sections of brain tissue • In situ hybridization is a method for localizing specific mRNA tra
More Less

Related notes for PSYCH 3AB3

Log In


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.