NGF regulation by lesion and estrogen treatment: Olfactory bulb lesions significantly increased NGF expression at 24 hours post injury (24 hpi). Estrogen treatment (OVX+E) increased basal and lesion-induced expression of NGF. However, anti-p75NTR had no effect on NGF expression in control pellet-replaced (OVX) or estrogen-replaced (OVX+E) animals. Bars represent means ± SEM, n = 6 per group. Sham: Sham lesion, Lesion+Vehicle: NMDA injection with pre immune serum, Lesion+Anti p75: NMDA injections with anti p75NTR antibodies. *:p < 0.05.