Complex sentence: The longer effects of kappa opioid agonism (30 minutes or greater) have been linked to kappa opioid dependent stress-induced potentiation and reinstatement of drug seeking through modulation of dopamine, serotonin, or norepinephrine and via activation of downstream signal transduction pathways.
Split into simpler sentences: The longer effects of kappa opioid agonism (30 minutes or greater) have been linked to kappa opioid dependent stress-induced potentiation and reinstatement of drug seeking. It is hypothesized that these behaviors are mediated by kappa opioid-dependent modulation of dopamine, serotonin, or norepinephrine and/or via activation of downstream signal transduction pathways.