yep, the good old cannabinoid receptors. And like someone allready said, it doesnt kill the brain cells like alcohol, it only makes them go "dormant" untill you stop smoking for awhile.

A Good Read http://www.amazon.com/exec/obidos/tg...70429?v=glance

http://www.cannabis.net/receptors/
http://www.nottingham.ac.uk/~mqzwww/cannabinoid.html
http://www.4adi.com/flr/cannabinoidflr.html
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract