the finding that self-administration of both the opiate heroin , inducing psychic and physical dependence , and the non-opiate cocaine , inducing psychic but not physical dependence , is accompanied by similar changes in beta e-ir concentrations particularly in limbic brain structures , and that these effects are present 18 h but not immediately after the last session , suggests that beta e and related peptides in limbic brain regions may represent a neurochemical correlate for psychic dependence on drugs .
C0086045
concentrations
C0006104
brain structures