The brain's own morphine and cigarette smoking: the junkie in disguise?
D000818:Animals; D001921:Brain / Q000378:metabolism*; D004723:Endorphins / Q000378:metabolism*; D006801:Humans; D011957:Receptors, Opioid / Q000032:analysis; D012907:Smoking
D004723:Endorphins; D011957:Receptors, Opioid