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Need help with transmitters and receptors

Larry larry at enigmatic.org
Fri Feb 13 22:48:30 EST 1998

    I am a senior in college taking a Neurobiology class and am having
difficulty with a question.  We are learning specifics about action
potentials and about different transmitters and receptors.
    The question is:

    "You are using the patch clamp recording method on a new kind of
neuron from a hippocampal slice.  When you stimulate a specific group of
input neurons, the frequency of inward current deflections increase.
The reversal potential of the events is around +50mV and is not blocked
by TTX.  Conventional transmembrane microelectrode recording reveals
that synaptic activation resulting in an EPSP is mimiced by application
of glutamate rather than ACh, norepinephrine or other transmitters.
Addition of GABA to the bath (surrounding the slice) decreases the EPSP
amplitude.  Addition of Peptide X, a putative neurotransmitter found in
the slice, slightly increases and extends the duration of glutamate's
    a.   Given the above observations what are the most likely molecular
events occurring after stimulation of the input neurons?
    b.   Why might GABA decrease the EPSP amplitude?  Explain if and how
GABA addition would affect the patch clamp (single channel recording)
data mentioned above.  Why?
    c.   List two possible molecular mechanisms that might be
responsible for peptide X's effect.
    d.   Describe an experiamnt that would distinguish between your two

Any help would be greatly appreciated.  I am having real difficulty with
this and no one can seem to help me.  Thank you very much for your time
and help.

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