basic question

Stephen Black sblack at UBISHOPS.CA
Tue Oct 1 09:09:22 EST 1996


On 30 Sep 1996, Pflieger Jean-Francois wrote:
> 
> First, synapses are not always unidirectional: a) Gap-junction are 
> bidirectional (even if not equally in the two direction, and b) a large 
> number of molecules which could act as retrograde messengers are now known 
> (arachidonic acid, NO...), and evidence accumulates for their role as 
> retrograde messengers. Second a antidromic action potential is 
> (generally?) stoped by the absence of Na-voltage dependent channels in the 
> body and dendrites of neurons. Third, an antidromic impulse could, 
> theorically, inhibit a receptor or synaptic potential; but I don't know 
> if there is proof or example for that. 

Thanks for the informative correction to my statement that conduction is 
always one-way across synapses (although it's a bit worrisome that my 
posts seem to be getting confused with those of Ken Collins). Kandell 
(and Schwartz and Jessell)'s latest book Principles of Neural Science and 
Behavior (Appleton & Lange, 1995), I've discovered, has a good discussion 
of the gap junction issue in chapter 11, which brings me to a further 
question:

Their examples of gap junctions are in the crayfish, goldfish, and marine 
snail. Is there any evidence for gap junctions in the mammalian CNS?

-Stephen

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Stephen Black, Ph.D.                      tel: (819) 822-9600 ext 2470
Department of Psychology                  fax: (819) 822-9661
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