Figure 1.

Localization of IL-1β mRNA in the rat brain by ISHH after treatment with LPS. In Figs. 1, 2, 3, 4, 5 images are representative of findings in six animals/group. A series of film autoradiographs is arranged from rostral to caudal (top to bottom), showing the regional pattern of IL-1β gene expression. Brain slices are shown in the first column (A–E) represent the hybridization of IL-1β antisense riboprobe in the brain of control rats, showing no detectable IL-1β mRNA. Two hours after a single LPS injection i.p. (5.0 mg/animal), the induction of IL-1β mRNA the brain is shown in the second column (F–J). There was induction of IL-1β mRNA in the choroid plexus (arrowhead in F) and subfornical organ (arrow in F), posterior pituitary (arrow in H), pineal (arrow in I), and meninges (arrow in J). Six hours after a single LPS injection, the induction of IL-1β throughout the brain is shown in the third column (K–O). There was a remarkable induction of IL-1β mRNA in the paraventricular nucleus of the hypothalamus (arrow in L); the induction in the choroid plexus (arrowhead in K), meninges (arrow in O), and in the subfornical organ (arrow in K) persists. Twenty-four hours after a single LPS injection the levels of IL-1β mRNA throughout the rat brain were considerably decreased (fourth column, P–T). (Bar = 1.3 cm.)