( Ergolines ( ( ( not only ) ( ( ( act ( on ( dopamine receptors ) ) ) but ) ( may ( have ( ( important effects ) ( on ( receptors ( for ( ( ( ( other chemicals ) ( in ( the brain ) ) ) , ) ( such ( as ( norepinephrine ( and ( serotonin receptors ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Ergolines)) (VP (CONJP (RB not) (JJ only)) (VP (VBP act) (PP (IN on) (NP (JJ dopamine) (NNS receptors)))) (CC but) (VP (MD may) (VP (VB have) (NP (NP (JJ important) (NNS effects)) (PP (IN on) (NP (NP (NNS receptors)) (PP (IN for) (NP (NP (JJ other) (NNS chemicals)) (PP (IN in) (NP (DT the) (NN brain))) (, ,) (PP (JJ such) (IN as) (NP (NN norepinephrine) (CC and) (NN serotonin) (NNS receptors))))))))))) (. .)))
Ergolines not only act on dopamine receptors but may have important effects on receptors for other chemicals in the brain, such as norepinephrine and serotonin 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))))) (. .)))