( ( Some ( of ( these ( receptors release ) ) ) ) ( ( ( dopamine , ) ( ( a chemical ) ( central ( to ( many ( brain functions ) ) ) ) ) ) ; ) )
(ROOT (S (NP (NP (DT Some)) (PP (IN of) (NP (DT these) (NNS receptors) (NN release)))) (VP (VBP dopamine) (, ,) (S (NP (DT a) (NN chemical)) (ADJP (JJ central) (PP (TO to) (NP (JJ many) (NN brain) (NNS functions)))))) (: ;)))
Some of these receptors release dopamine, a chemical central to many brain functions;
(ROOT (S (NP (NNP Addiction)) (VP (VBZ affects) (NP (NP (DT the) (JJ dopamine) (NNS receptors)) (PP (IN within) (NP (DT the) (NN brain))))) (. .)))