Platelet serotonin promotes the recruitment of neutrophils to sites of acute inflammation in mice.

The majority of peripheral serotonin is stored in platelets, which secrete it on activation. Serotonin releases Weibel-Palade bodies (WPBs) and we asked whether absence of platelet serotonin affects neutrophil recruitment in inflammatory responses. Tryptophan hydroxylase (Tph)1­deficient mice, lacking non-neuronal serotonin, showed mild leukocytosis compared with wild-type (WT), primarily driven by an elevated neutrophil count. Despite this, 50% fewer leukocytes rolled on unstimulated mesenteric venous endothelium of Tph1(-/-) mice. The velocity of rolling leukocytes was higher in Tph1(-/-) mice, indicating fewer selectin-mediated interactions with endothelium. Stimulation of endothelium with histamine, a secretagogue of WPBs, or injection of serotonin normalized the rolling in Tph1(-/-) mice. Diminished rolling in Tph1(-/-) mice resulted in reduced firm adhesion of leukocytes after lipopolysaccharide treatment. Blocking platelet serotonin uptake with fluoxetine in WT mice reduced serum serotonin by > 80% and similarly reduced leukocyte rolling and adhesion. Four hours after inflammatory stimulation, neutrophil extravasation into lung, peritoneum, and skin wounds was reduced in Tph1(-/-) mice, whereas in vitro neutrophil chemotaxis was independent of serotonin. Survival of lipopolysaccharide-induced endotoxic shock was improved in Tph1(-/-) mice. In conclusion, platelet serotonin promotes the recruitment of neutrophils in acute inflammation, supporting an important role for platelet serotonin in innate immunity.

The effects of antidepressants on the results of skin prick tests used in the diagnosis of allergic diseases.

BACKGROUND: Some drugs may cause false negative results by suppressing the reactivity of the skin prick tests (SPTs). The aim of this survey was to show whether escitalopram, fluoxetine and sertraline had any effect on the reactivity of SPT. METHODS: Twenty-four patients who were admitted to the outpatient clinic of the Psychiatry Department at the Hacettepe University Hospital and planned to be treated by these antidepressants were included in the study between May and October 2008. SPTs with positive control (histamine), negative control and 3 common aeroallergens were performed in the beginning, at the first and fourth weeks. A questionnaire including 26 questions about respiratory symptoms and allergic diseases was filled in face to face by the fellow-in-training. The Visual Analog Scale (VAS) of current respiratory and nasal symptoms was recorded at all 3 visits. RESULTS: There were no statistically significant differences between the 3 mean diameters measured at 3 time points in addition to the mean diameters of the wheals between groups using escitalopram, sertraline and fluoxetine (p > 0.05). There was a statistically significant decrease between the VAS of nasal symptoms at the 3 visits (p < 0.05). CONCLUSIONS: Escitalopram, fluoxetine and sertraline do not seem to affect the reactivity of SPTs. Nasal symptoms might have been decreased due to both the allergic treatment suggested and the end of the pollen season.

Adverse cutaneous reactions associated with fluoxetine strategy for reintroduction of this drug in selected patients.

Four patients treated with fluoxetine alone developed generalized urticaria. One also suffered polyarthritis. These reactions subsided when fluoxetine was stopped. After 6-12 months, because of progressive psychiatric problems, fluoxetine was reintroduced using a desensitization protocol. In each case this was well tolerated, and fluoxetine has been continued without adverse affects for 3-10 months.

Structured group therapy and fluoxetine to treat depression in HIV-positive persons.

In 1990, 20 asymptomatic persons diagnosed with the human immunodeficiency virus (HIV-positive) and mild-to-moderate depression were divided into 2 comparison groups. One group received structured group therapy plus fluoxetine, while the other received the same therapy plus a placebo. Affective, neurocognitive, and immune variables were measured before and after the intervention. In the patients receiving group therapy and fluoxetine, its administration did not improve treatment outcome compared to the therapy and placebo group. No significant differences between the two groups were noted on immune variables. However, symptoms of depression decreased in both groups, and both groups showed significant incorporation of the skills in active behavioral coping taught in therapy.