Posted by fachad on March 24, 2002, at 3:20:22
In reply to ISO: thx, but still can't find simple def of recep » IsoM, posted by Janelle on March 23, 2002, at 22:44:32
Janelle,
Here's my crack at a simple definition of a receptor.
A receptor is a thing on a nerve cell that is activated by a chemical neurotransmitter. Always think of receptors and neurotransmitters as a pair. Serotonin is a chemical neurotransmitter, which acts at a serotonin receptor.
Very simply put, think of a receptor as a keyhole, and a neurotransmitter as a key that fits into that keyhole.
A drug can bind with a receptor because its structure is similar enough to the natural neurotransmitter to fit into the keyhole. It can fit in, and act like the drug, like a master key of a locksmith. In that case it is an "agonist" or assister of the neurotransmitter / receptor pair.
A drug can also bind with a receptor, not act like the neurotransmitter, and block the natural action of the neurotransmitter, like someone pouring glue into a keyhole, making it impossible for the lock to be used. In this case it is an antagonist.
I guess an analogy would be a taste bud. You have them on your tongue, and they are taste receptors. There are "sweet" receptors, "salty" receptors, etc. The similarity is that taste buds, like receptors, are "organs" that respond to one specific thing. For taste buds, its sweet, salty, etc. For receptors, its NE, 5HT, ACH, etc.
The difference between taste buds and receptors in your nervous system is that all taste buds do one thing - send taste sensations to your brain.
But receptors can do just about anything. They can excite the nerve downstream of the receptor. They can inhibit the nerve downstream of the receptor. They can excite or inhibit the nerves upstream of the receptor. The can cause the release of the chemical that activates them, or they can inhibit the release of the chemical that activates them. They can cause the release of other transmitters. There are a huge number of possibilities and that is why it seems so complicated to you.
But basically the keyhole / chemical key analogy is enough to roughly understand what is going on.
> ISO - I clicked on those three great links you provided but still couldn't find a simple, basic definition of a receptor! When I clicked on "R" in that bio textbook, Receptor wasn't even listed!
>
> Can you possibly explain what a receptor is (does it just receive chemicals or does it release them also, what does the darn thing do?!!!)
poster:fachad
thread:99715
URL: http://www.dr-bob.org/babble/20020322/msgs/99798.html