Thank you ma-en,
After a bit of research on the topic I have made the following dicoveries and feel I should clearup any misinformation. First off it would be unusually difficult to kill anything with ecstacy. Overdoses of e are rarely fatal. A human dose to a cat would most likely not kill the cat but would increase negative side effects to an intollerable level. Lab animals (mice, rats and rhesus monkeys), unfortunately, have been exposed to extreemly high doses of mdma sometimes on a daily basis, subcutaneously/subdermally (injected under the skin or into the muscle - a much more direct and potent delivery method). And while these tests have not concluded e to be toxic to the point of fatality at these doses, it has overwhelmingly shown mdma to be a neurotoxin. In other words it can and does cause specific and signifigant damage to certain parts of the brain, most noteably to seratonin producing and recieving cells. One or more tests (on mice) has shown this damage to be reversable, at least in terms of seratonin production and metabolization within the brain, however the effected cells and/or dendrites may be permanently changed or damaged. A certain amount of this most likely occurs in our brains too, given a normal dose, but relatively little when compared to the large doses that lab animals or frequent users are exposed to.
Also it is important to keep in mind that ecstacy is a stimulant and not an halucenogen and therefore drawing any comparison between acid or mushrooms and e would be faulty. For example slipping me acid at a croweded mal can not accurately be compared to giving a cat e. Seratonin has pretty much the same function accross mamalian brains. It is closely associated with sensory input and mood regulation. Our brains via evolution have developed to specialize and have strengths in the areas of social and creative information processing. Seratonin most likely plays a large roll in how sensory input information is processed both qualitatively and quantitatively. Evolutionarilly speaking cats have been optimized for hunting or mousing (hunting for small animals). Stimulating senses and informational processors of cats may be plesurable for them, or it may very well be very unpleasant. It would seem obvious to me that cat very much enjoy focusing their senses and behaviors for such activites as stalking and hunting as well as getting stroked, lounging on an warm blanket, and even preening (especially preening). However it may or may not be the case that over stimulation of a cats seratonergic system increases the enjoyment of these cat activities. It may very well be distracting, annoying or downright uncomfortable for them. And as far as mood regulation is concerned it seems to be closely associated with pleasure across mammal species, but it is important to keep in mind that we don't understand the process in ourselves or cats.
As far as weed is concerned, I doubt that all animals enjoy it's effects. I have tried it several times, rarely with positive results. I have always felt somewhat confused and parnoid, sometimes to the point of panic. If anyone knows what I am doing wrong please let me know.
Thank you all,
surfaceNoise