Changes in the skin microvessel permeability following destruction of the mamillary-tegmental tract in normal and capsaicin-treated rats

An increase in vascular permeability as measured by the Evans Blue dye leakage into forepaws, was observed 1 hour following the destruction of mamillo-tegmental tracts in rats. Ten days after capsaicin pre-treatment the destruction did not induce any changes of the microvascular permeability in the skin forepaws. The findings suggest that the descending projections of hypothalamic mamillary nuclei might regulate the mechanisms of the skin microvessel permeability, the action being mediated through capsaicinsensitive neurons of the spinal ganglion.