Posted by Scott L. Schofield on April 19, 2000, at 12:35:21
In reply to Serotonin and dopamine opposition - Railroaded, posted by Scott L. Schofield on April 19, 2000, at 11:17:42
I guess I better comment further on the words "oppose" and "opposition".
The concept of opposition is appropriate when dealing with interactions between neural pathways and subsystems. I guess the one that would provide the best example of this would be the balance that exists between the sympathetic and parasympathetic components of the autonomic nervous system. These two subsystems exert opposing influences on the same organs.
Cam understands this stuff much better than I, but I will jot down a few things that he may want to comment on, add to, and correct.
1. Sympathetic - "fight or flight" - Norepinephrine
- Increases heart rate
- Increases blood pressure
- Shunts blood from the gut and skin to the skeletal muscles
- Decreases pupil diameter
- Decreases blood flow to the genitals2. Parasympathetic - "Eat and have sex" - Acetylcholine
- Decreases heart rate
- Decreases blood pressure
- Shunts blood from the skeletal muscles to the gut and skin.
- Dilates pupils
- Increases blood flow to the genitals
* Norepinephrine becomes involved later on - orgasm.I think the qualification of this interaction can be served by the word "oppose". However, this opposition is accomplished by complex mechanisms and interactions that include neuronal modulation, negative feedback loops, positive feedback loops, and the competition for the activation or inhibition of target nuclei, pathways and subsystems.
It is impossible to describe the brain and nervous system in just one post. Sorry. :-)
- Scott
poster:Scott L. Schofield
thread:29285
URL: http://www.dr-bob.org/babble/20000411/msgs/30584.html