endorphin question

[dimethylether]

Hello I did some Googling but can't seem to be able to figure this out.

 

The difference between iso pentane and neo pentane is in the molecular structure, they both have 5 carbon atoms.

 

1. why is endorphin so different from neo endorphin? endorphin has nearly 3x the number of carbon atoms as neo-endorphin

 

2. what's the practical function of neo-endorphin and endorphin? which is the 'happy' chemical?

 

3. in terms of practical purpose, which is more important, alpha or beta endorphin?

 

Thanks