ACTIVATION OF CORTICOTROPIN-RELEASING FACTOR-CONTAINING NEURONS IN THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS BY INTERLEUKIN-1 IN THE RAT

Interleukin-1 (IL-1) alpha was injected into the lateral ventricle of the rat. An antiserum against Fos oncoprotein was used to detect the activated neurons immunohistochemically. A large number of neurons in the parvocellular paraventricular nucleus of the hypothalamus, in an area corresponding to the location of the corticotropin-releasing factor (CRF)-containing neurons, were strongly Fos-like immunoreactive (LI). Double immunostaining for Fos and CRF revealed that many of the Fos-LI cells were CRF-LI. Furthermore, the CRF-like immunoreactivity was greatly enhanced in the rats injected with IL-1 alpha, indicating an increase in CRF synthesis.