D1 and D2 both refer to specific types of dopamine receptors.

I'm sure it has something to do with the fact that the D1 receptors are in regions different from D2 receptors.

I know that adenylate cyclase usually triggers a signal transduction cascade that leads to increased cAMP+calmodulin, resulting in increased gene expression of proteins that help promote long-term potentiation of postsynaptic neurons (presumably lowering the absolute value of the voltage threshold that's needed to trigger another action potential, which increases neuron excitability).

But an increase in dopamine is going to cause more neuron excitability in postsynaptic neurons in some regions (those that have D1 receptors), and less in others (those that have D2 receptors). What then explains the fact that increased expression at all dopamine receptors can help modulate attention span?

I know that D3 and D4 are also involved, but they have to be either excitatory, inhibitory, or neutral.

  • $\begingroup$ Could you please split your questions into several ones? You currently ask 3 questions within the text and the question in the title seems to be the 4th question unrelated to the previous ones. $\endgroup$ Commented Jan 21, 2012 at 21:05
  • $\begingroup$ okay I've deleted the separate questions for now. $\endgroup$ Commented Jan 22, 2012 at 0:32
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    $\begingroup$ There are two problems with your hypothesis: 1) you cannot assume that the same receptor will be involved in the same process all over the brain and 2) you cannot assume that something as complex as attention span be the result of the action of only one receptor. $\endgroup$
    – nico
    Commented Jan 22, 2012 at 7:45
  • $\begingroup$ 1) Okay - that's true. I think that would serve as the basis for a follow-up question about where D1 receptors are expressed relative to D2 receptors - I've asked it biology.stackexchange.com/questions/752/…. 2) That's also true, but changes to one receptor most certainly do affect attention span. $\endgroup$ Commented Jan 22, 2012 at 15:52
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    $\begingroup$ @InquilineKea: they probably do, but the result may be indirect and dependent on other factors. I do not know enough about that to give you a proper answer though $\endgroup$
    – nico
    Commented Jan 22, 2012 at 18:46


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