Indications for a „brain-hair follicle axis (BHA)“: inhibition of keratinocyte proliferation and up-regulation of keratinocyte apoptosis in telogen hair follicles by stress and substance P. - Arck,P.C.; Handjiski,B.; Hagen,B.; Hagen,E.; Joachim,R.; Klapp,B.F.; Paus,R. (FASEB J, 2001)