Penny: Sheldon?
Sheldon: Mm, absolutely not, no. The Nobel committee will be making the calls to inform the winners at any minute, so the only drug I need is the endorphins pumping through my brain in anticipation of our victory.
Amy: Well, technically, anticipation wouldn't be mediated by endorphins as much as dopamine, but, you know, you've been up all night, so I'll give you that one. [Amy looks and sees Sheldon is asleep] Really? The second he stops talking?