Reduced intracellular platelet Ca2+ responses to serotonin in patients with anorexia and bulimia nervosa increase under antidepressant medication

Introduction: Past research has indicated that the serotonergic (5-HT) system is involved in the pathophysiology of eating disorders.There is evidence that the stimulation of 5-HT2-receptors in platelets is a useful peripheral model to investigate the cascade of signal transduction and neuronal functioning. Methods: 26 anorexic, 12 bulimic and 5 obese female patients between the ages of 11 and 18 years (15,4±2,0 years) participated in this study. The control group consisted of 21 healthy female adolescents. 5-HT stimulated intracellular Ca2+ response was obtained using the Fura-2 method at the time of admission, during therapy and at the end of inpatient treatment. Results: We observed a significant decrease in 5-HT-induced Δ[Ca2+]i in both anorexic (p<0.01) and bulimic patients (p<0.05) compared to healthy controls, but not in obese patients at the time of admission. Antidepressant treatment led to a significant increase of Δ[Ca2+]i in anorexic and bulimic patients (both p<0.05) by the end of treatment. Moreover, there was an even stronger decrease in Δ[Ca2+]i of un-medicated anorexic patients (p<0.05). In bulimic patients without antidepressive medication the Δ[Ca2+]i did not show any significant changes under therapy. Conclusions: We conclude that in patients suffering from anorexia or bulimia the signaling pathways are disturbed, but not in patients with obesity. The administration of antidepressants lead to an improved 5-HT transmission in anorectics and bulimics.