Psychopharmacology
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Randomized Controlled Trial
Does modafinil activate the locus coeruleus in man? Comparison of modafinil and clonidine on arousal and autonomic functions in human volunteers.
Modafinil is a wakefulness-promoting drug which is likely to activate some wakefulness-promoting and/or inhibit sleep-promoting neurones in the brain. The locus coeruleus (LC) is a wakefulness-promoting noradrenergic nucleus whose activity can be "switched off" by the alpha2-adrenoceptor agonist clonidine, leading to sedative and sympatholytic effects. ⋯ Clonidine exerted sympatholytic and sedative effects, whereas modafinil had sympathomimetic and some alerting effects. Modafinil may activate noradrenergic neurones in the LC involved in arousal and pupillary control, without affecting extracoerulear noradrenergic neurones involved in cardiovascular and salivary regulation.
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Controlled Clinical Trial
Reinforcing effects of oral Delta9-THC in male marijuana smokers in a laboratory choice procedure.
Oral Delta-9-tetrahydrocannabinol (Delta(9)-THC; Marinol) is medically available for the treatment of nausea associated with cancer chemotherapy and for wasting syndromes related to HIV/AIDS. Little is known about its reinforcing effects. ⋯ These data indicate that oral Delta(9)-THC may have modest abuse liability in experienced marijuana smokers.
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Subchronic administration of stimulants reduces basal dopamine (DA) concentrations and blocks stress-induced DA release in the nucleus accumbens (NA) of rats during withdrawal. However, no studies have attempted to relate early withdrawal from chronic drug exposure to stress reactivity and changes in DA transmission. ⋯ These results suggest that subchronic METH exposure selectively increases NA DAT and consequently reduces basal and stress-induced DA release in the NA SHELL during early withdrawal.
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Comparative Study
Ultra-low-dose naltrexone suppresses rewarding effects of opiates and aversive effects of opiate withdrawal in rats.
Ultra-low-dose opioid antagonists enhance opiate analgesia and attenuate tolerance and withdrawal. ⋯ Ultra-low-dose NTX coadministration blocks the acute rewarding effects of analgesic doses of oxycodone or morphine as well as the anhedonia of withdrawal from chronic administration.