(a) Cocaine is obtained from coca plant Erythroxylum coca. It affects the transport of the neuro-transmitter dopamine.
(b) Opioids are the drugs, receptors present in our central nervous system and gastrointestinal tract Heroin (smack the depressant,it is prepared by the acetylation of morphine which is extracted from the latex of poppy plant Papaversomniferum.
