Can a serotonin type 3 (5-HT3) receptor antagonist reduce experimentally-induced itch?
BACKGROUND
Serotonin type 3 (5-HT3) receptor antagonists have been reported to be a novel therapeutic principle for the treatment of cholestatic and uremic pruritus.


OBJECTIVE
To determine the antipruritic effect of a 5-HT3 receptor antagonist (tropisetron) on histamine and serotonin-induced itch under experimental conditions in comparison to native skin and after pretreatment with an orally applied antihistamine (cetirizine).


METHODS
Histamine and serotonin were iontophoretically applied in 10 healthy volunteers. Wheals and flares were planimetrically evaluated. Itching and burning sensations were entered on a scale over 24 min. The examination also comprised alloknesis, elicitation of perifocal itch sensation by usually non-itching (e.g. mechanical) stimuli.


RESULTS
Tropisetron did not have any significant influence on histamine-induced reactions but could significantly reduce serotonin-induced flares. Cetirizine led to a significant reduction of all histamine-induced parameters and abolished serotonin-induced wheals.


CONCLUSIONS
Serotonin has an own pruritic potency and does not only act over histamine containing mast cells. The antipruritic effect of tropisetron reported in cholestatic and uremic pruritus could not be verified in healthy persons under experimental conditions.
Weisshaar
E
E
Department of Dermatology and Venereology, University of Magdeburg, Germany. Elke.Weisshaar@medizin.uni-magdeburg.de
Ziethen
B
B
Gollnick
H
H
D000328:Adult; D017332:Cetirizine / Q000627:therapeutic use; D005260:Female; D006632:Histamine / Q000008:administration & dosage; D006634:Histamine H1 Antagonists / Q000627:therapeutic use; D006801:Humans; D007211:Indoles / Q000627:therapeutic use*; D007478:Iontophoresis; D008297:Male; D011537:Pruritus / Q000139:chemically induced / Q000188:drug therapy*; D012701:Serotonin / Q000008:administration & dosage; D012702:Serotonin Antagonists / Q000627:therapeutic use*; D012881:Skin Temperature; D000077526:Tropisetron
D006634:Histamine H1 Antagonists; D007211:Indoles; D012702:Serotonin Antagonists; D012701:Serotonin; D000077526:Tropisetron; D006632:Histamine; D017332:Cetirizine