Opioid drugs +opioid peptides?

[jawad salam]

Hi,
I am a finalist studying biochemistry in particular neurobiology.
Could somebody please explain to me how opiate drugs and opiod peptides 
produce their narcotic and analgesic effects? Any information would be 
greatly appreciated. Thankyou.

Jawad
-- 
--------------------------------------------------------------------------
| jawad salam    EMail jawad at salam.demon.co.uk                  
--------------------------------------------------------------------------