Well-maintained reflex responses of sympathetic nerve activity to stimulation of baroreceptor, chemoreceptor and cutaneous mechanoreceptors in neonatal capsaicin-treated rats.

Neonatal treatment with capsaicin (CAP) reduced the content of substance P-like immunoreactivity in the area of the nucleus tractus solitarii and the dorsal horn of the spinal cord in rats. The resting values of the mean arterial blood pressure and heart rate of CAP-treated rats were not significantly different from those of control rats. Reflex responses of the renal sympathetic nerve activity to stimulation of baroreceptor, chemoreceptor and cutaneous mechanoreceptor were compared in CAP- and vehicle-treated rats. Under these conditions the reflex responses were quite well maintained in CAP-treated rats.