Double-blinded randomized prospective trial of intranasal capsaicin treatment for nonallergic rhinitis.

BACKGROUND: Nonallergic rhinitis (NAR) is currently a diagnosis of exclusion with an unclear pathophysiologic mechanism and limited treatment options. In patients diagnosed with NAR based on symptoms, negative skin testing and positive optical rhinometry (ORM), the study's objective was to evaluate the therapeutic action of intranasal capsaicin in the management of rhinitic symptoms and the effect on ORM readings. METHODS: Patients with a history of NAR underwent screening by a diagnostic intranasal capsaicin challenge with ORM and skin-prick testing. Twenty-two NAR patients were enrolled and randomized to either treatment with 0.1mM capsaicin (n = 11) or placebo (n = 11). Treatment consisted of 5 consecutive intranasal applications separated by 1 hour with follow-up at 4 and 12 weeks. At each visit, subjects underwent intranasal capsaicin challenge with ORM reading and a visual analog scale scoring of rhinitis symptoms. RESULTS: Treatment with intranasal capsaicin resulted in a median change with improvement in total symptom score (TSS) of -5 from baseline vs an increase of 2 with placebo at 4 weeks, which remained significantly different between the groups at 12 weeks (p = 0.03). At 12 weeks posttreatment, 60% of the intervention group vs 80% of placebo-treated patients still met objective criteria for NAR by ORM. CONCLUSION: Using ORM in the objective diagnosis of NAR, this trial showed that intranasal 0.1mM capsaicin not only improved rhinitic symptoms but also objectively reduced nasal reactivity and nasal congestion with a 40% responder rate at 12 weeks as noted by ORM.

Previous exposure to psychostimulants enhances the reinstatement of cocaine seeking by nucleus accumbens AMPA.

The effect of previous exposure to psychostimulants on the subsequent self-administration of cocaine as well as reinstatement of this behavior by priming infusions of AMPA into the nucleus accumbens (NAcc) was examined. Rats were exposed to five injections, one injection every third day, of either saline or amphetamine (AMPH: 1.5 mg/kg, i.p.). Starting 10 days later, they were trained to self-administer cocaine (0.3 mg/kg/infusion, i.v.) and subsequently tested under a progressive ratio (PR) schedule for 4 consecutive days. As expected, rats exposed to AMPH worked more and obtained more cocaine infusions than saline exposed controls on the PR test sessions. Following daily extinction sessions during which saline was substituted for cocaine, the effect of priming infusions of AMPA (0.0, 0.08, or 0.8 nmol/0.5 microl/side) into the NAcc was then examined on two tests: one conducted 4 days after the last cocaine PR test session (2-3 weeks after the last AMPH exposure injection) and the next 4 weeks later. Consistent with previous reports, NAcc AMPA dose-dependently reinstated cocaine seeking on both tests regardless of exposure condition. Importantly, this priming effect of NAcc AMPA was significantly enhanced in AMPH compared to saline exposed rats on the first test conducted 2-3 weeks after AMPH. On the second test, conducted 4 weeks after cocaine, reinstatement was similarly enhanced in both groups to levels observed on the first test in AMPH exposed rats. These results indicate that both noncontingent (AMPH) and contingent (cocaine) exposure to psychostimulants enhances the reinstatement of cocaine seeking by NAcc AMPA and appears to do so in a time-dependent manner.