Effect of lesion of the hypothalamic mamillary nuclei on skin blood vessel permeability in normal and capsaicin-pretreated rats.

Contralateral increased exudation of plasma proteins, as measured by Evans Blue leakage into the fore paws, was produced by unilateral electrocoagulation of the mamillary nuclei in rats. Ten days after adult capsaicin pretreatment (increasing doses/4 days total 200 mg/kg, s.c.) the unilateral destruction of these nuclei did not evoke any changes of skin blood vessel permeability in both contralateral and unilateral paws. The findings show that the central nervous system may modulate the capsaicin-sensitive peptidergic neuron action on blood vessel permeability.