Axon collaterals ?
rsn_ at _comcast.net
Thu Jan 1 22:35:15 EST 2004
On Fri, 02 Jan 2004 12:17:46 +1100, Matthew Kirkcaldie
<Matthew.Kirkcaldie at removethis.newcastle.edu.au> wrote:
>In article <erk3uvs9tqjkgkg2fklq2o4fls4u05ne2s at 4ax.com>,
> r norman <rsn_ at _comcast.net> wrote:
>> Yes. Even glutamate has both in the retina. I misspoke
>> about "all" the known glutamate receptors. Glutamate is
>> "ordinarily" excitatory in the CNS.
>What's the inhibitory glutamate receptor in the retina?
>While we're on the subject, it's worth remembering that GABA is
>excitatory in the immature CNS.
The synapse from receptor to bipolar is supposed to be glutamatergic,
even though "on" and "off" bipolars have opposite responses. Here is
Grant GB, Dowling JE
A glutamate-activated chloride current in cone-driven ON
bipolar cells of the white perch retina.
J Neurosci. 1995 May;15(5 Pt 2):3852-62
Grant GB, Dowling JE.
On bipolar cell responses in the teleost retina are generated by
two distinct mechanisms.
J Neurophysiol. 1996 Dec;76(6):3842-9
I learned of it from indirect souces like a Neuro text (which one I
don't remember) or
How the Retina Works
American Scientist 91:28 (2003)
However, the situation may be complicated -- the glutamate response
may be indirect and actually mediated by GABA -- see
Membrane currents evoked by ionotropic glutamate receptor
agonists in rod bipolar cells in the rat retinal slice preparation.
J Neurophysiol. 1996 Jul;76(1):401-22.
Invertebrate are more clearcut -- there are distinct inhibitory
glutamate receptors as described in
Inhibitory glutamate receptor channels.
Mol Neurobiol. 1996 Oct;13(2):97-136
Thomas A. Cleland and Allen I. Selverston
Dopaminergic Modulation of Inhibitory Glutamate Receptors in
the Lobster Stomatogastric Ganglion
J Neurophysiol 78: 3450-3452, 1997
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