Psychopharmacology
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Randomized Controlled Trial
Human abuse liability assessment of oxycodone combined with ultra-low-dose naltrexone.
Prescription opioid abuse has risen dramatically in the United States as clinicians have increased opioid prescribing for alleviation of both acute and chronic pain. Opioid analgesics with decreased risk for abuse are needed. ⋯ The addition of ultra-low-dose NTX to OXY did not decrease abuse liability of acutely administered OXY in experienced opioid abusers.
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Social stress has been linked to several neuropsychiatric diseases, including depression, which is a debilitating disease that has genetic, environmental, and epigenetic underpinnings. ⋯ These results indicate that social defeat induces several long-lasting depressive-like behaviors in rats and induces a significant, short-lived increase in H3 acetylation in the hippocampus, although the underlying mechanism behind this change warrants further investigation.
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Individual differences in impulsive decision-making may be critical determinants of vulnerability to impulse control disorders and substance abuse, yet little is known of their biological or behavioural basis. The orbitofrontal cortex (OFC) has been heavily implicated in the regulation of impulsive decision-making. However, lesions of the OFC in rats have both increased and decreased impulsivity in delay-discounting paradigms, where impulsive choice is defined as the selection of small immediate over larger delayed rewards. ⋯ Providing explicit environmental cues to signal the delay-to-reinforcement appears to change the way in which the OFC is recruited in the decision-making process in a baseline-dependent fashion. This change may reflect activation of the dopamine system, as intra-OFC infusions of dopamine receptor antagonists increased impulsive choice but only when the delay was cued.