( There ( ( are ( ( ( ( at least ) 5 ) types ) ( of ( dopamine receptors ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (QP (IN at) (JJS least) (CD 5)) (NNS types)) (PP (IN of) (NP (JJ dopamine) (NNS receptors))))) (. .)))
There are at least 5 types of dopamine receptors.
(ROOT (S (NP (NNP Addiction)) (VP (VBZ affects) (NP (NP (DT the) (JJ dopamine) (NNS receptors)) (PP (IN within) (NP (DT the) (NN brain))))) (. .)))