Dose-dependent response of mature cerebrovascular axons in vivo following intracranial infusion of nerve growth factor

Abstract

The perivascular axons associated with the intradural segment of the internal carotid artery undergo a sprouting response following intracerebroventricular infusion of nerve growth factor (NGF). The objective of the present study was to determine whether a relationship exists between the number of sprouted axons and the amount of NGF infused into the ventricular system. Using regression analysis, we observed a significant log-log relationship between the dose of NGF and number of axons. No significant relationship was observed for the control (VEH) group. A significant increase in axonal number was observed following infusion of 3.0 μg NGF and higher when compared with VEH treatment of similar concentration. Results of this analysis suggest that a maximal response to NGF is approximated at doses of 15 μg or higher. These findings suggest a dose-dependent relationship between the response of mature sympathetic cerebrovascular axons in vivo and the dose of exogenous NGF.