RT Journal Article
SR Electronic
T1 Dopaminergic mechanisms of opiate actions in brain.
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 50
OP 57
VO 192
IS 1
A1 E Eidelberg
A1 R Erspamer
YR 1975
UL http://jpet.aspetjournals.org/content/192/1/50.abstract
AB We have studied the interactions between morphine and a dopamine-blocking agent (haloperidol) and a dopamine precursor, L-3,4-dihydroxyphenylalanine (L-dopa). We found that haloperidol potentiated morphine-induced analgesia and enhanced morphine tolerance. Morphine-tolerant mice exhibited enhanced sensitivity to the locomotor excitatory actions of L-dopa. We propose that morphine exerts some of its central nervous actions by first interfering with dopamine-mediated synaptic transmission and then initiating compensatory changes that superficially resemble denervation supersensitivity. These compensatory changes may underlie the excitatory actions of morphine.