Imaging the norepinephrine transporter in humans with (S,S)-[11C]O-methyl reboxetine and PET: problems and progress.

Unlabelled: Results from human studies with the PET radiotracer (S,S)-[(11)C]O-methyl reboxetine ([(11)C](S,S)-MRB), a ligand targeting the norepinephrine transporter (NET), are reported. Quantification methods were determined from test/retest studies, and sensitivity to pharmacological blockade was tested with different doses of atomoxetine (ATX), a drug that binds to the NET with high affinity (K(i)=2-5 nM).

Methods: Twenty-four male subjects were divided into different groups for serial 90-min PET studies with [(11)C](S,S)-MRB to assess reproducibility and the effect of blocking with different doses of ATX (25, 50 and 100 mg, po).

High-affinity CRF1 receptor antagonist NBI-34041: preclinical and clinical data suggest safety and efficacy in attenuating elevated stress response.

There is an extensive evidence that corticotropin releasing factor (CRF) is hypersecreted in depression and anxiety, and blockade of CRF could have therapeutic benefit. We report preclinical data and the results of a clinical Phase I study with the novel nonpeptide CRF(1) antagonist NBI-34041/SB723620. Preclinical data conducted with different cell lines expressing human CRF receptors and in Wistar and Sprague-Dawley rats indicate that NBI-34041 is effective in reducing endocrine responses to pharmacological and behavioral challenge mediated by CRF(1) receptors.

The slow and long-lasting blockade of dopamine transporters in human brain induced by the new antidepressant drug radafaxine predict poor reinforcing effects.

Background: (2S,3S)-2-(3-Chlorophenyl)-3,5,5,-trimethyl-2-morpholinol hydrochloride (radafaxine) is a new antidepressant that blocks dopamine transporters (DAT). A concern with drugs that block (DAT) is their potential reinforcing effects and abuse liability. Using positron emission tomography (PET) we have shown that for DAT-blocking drugs to produce reinforcing effects they must induce >50% DAT blockade and the blockade has to be fast (within 15 minutes).

A Review of the Neuropharmacology of Bupropion, a Dual Norepinephrine and Dopamine Reuptake Inhibitor.

BACKGROUND: The neurochemical and biological effects of antidepressant medications have become better defined over the last decade. When the anti-depressant bupropion was introduced in the United States in 1989, the specific pharmacologic basis of its clinical effects was uncertain. Research conducted over the past decade has significantly advanced the understanding of the neuropharmacology of bupropion and has demonstrated a novel mechanism of antidepressant activity.

In vivo activity of bupropion at the human dopamine transporter as measured by positron emission tomography.

Background: Converging lines of evidence are consistent with an inhibitory effect of the antidepressant and smoking-cessation aid bupropion on dopamine and norepinephrine reuptake, but the in vivo effects of the drug at the human dopamine transporter (DAT) have not been studied to date. This study employed positron emission tomography (PET) to assess the extent and duration of DAT receptor occupancy by bupropion and its metabolites under conditions of steady-state oral dosing with bupropion sustained-release (SR) in healthy volunteers.

Methods: Six healthy male volunteers received bupropion SR 150 mg daily on days 1 through 3 and 150 mg every 12 hours on day 4 through the morning of day 11.

Estimation of the effect of food on the disposition of oral 5-fluorouracil in combination with eniluracil.

Aims: To determine the effect of food on the pharmacokinetics of 5-fluoruracil (5-FU) taken orally with eniluracil and to compare the performance of different pharmacokinetic analysis methods in the detection a potential food-drug interaction.

Methods: In a randomized, open-label, two-way crossover study, 12 patients received eniluracil (50 mg, orally) on days 1 and 2 and 5-FU (20 mg/m(2), orally) on day 2 following either a 2-h fast or 20 min after a standard meal. Treatments were separated by 7 days.