Posted by Larry Hoover on December 10, 2004, at 9:03:29
In reply to Re: dopamine autoreceptor problem...Lar » raybakes, posted by tealady on December 7, 2004, at 18:08:55
> My guess is that autoreceptors have to be by definition pre-synaptic. In books I just looked up the term seems to be the same.
Yes, auto-receptors are the feedback to the cell releasing a neurotransmitter. The releasing cell has to have a way of measuring how strong its own signalling is, as it is otherwise not connected to the cells on the other side of the synapse (but for synapses arranged in the reverse direction).
> But I would have thougt that presynaptic receptors could have feedback by other things other than "self" and I get the impression that autoreceptors are receptors in the same synapse that released them..so unsure if autoreceptors are a subset of presynaptic or the one and same term...
When a neurotransmitter is released into the synapse, it does so by rupturing a vescicle, something like a bubble, that stores neurotransmitters in fluid. Vescicles do not contain pure neurotransmitters. They are always a blend. They will contain inhibitory substances like GABA or taurine, or excitatory ones like glutamate or acetylcholine, along with the dopamine or serotonin or whatever is being released. The autoreceptors can sense both the primary neurotransmitter, and the modulating ones. Autoreceptors tend to be dimerized (or even polymerized), to detect multiple ligands simultaneously.
> Autoreceptors can inhibit or facilitate release of neurotransmitters.See above. Probably through modulators simultaneously released, and the primary signal intensity, somehow integrated by second messengers.
> Ganong "Review of medical physiology" pp 96 mentions receptors
>
> it says (as one would expect) prolonged exposure to their ligands causes most receptor to become unresponsive..ie to undergo desensitization.That's due to saturation. It's the same process that causes e.g. the sense of smell to be accustomed to a strong stimulus over time.
> > Just started reading a book called "prozac backlash" It talks about SSRIs inhibiting dopamine, and so dramatically reducing female hormones. I wonder whether autoimmunity increases with SSRIs, what do you think?
> >
> > Ray
> >
> Yes Ray, probably all true. I just enjoy tearing up scripts for SSRI's in the past few years..
>
> JanLar
poster:Larry Hoover
thread:413185
URL: http://www.dr-bob.org/babble/alter/20041123/msgs/427146.html