Adrenocortical activation by herpes virus: involvement of IL-1 beta and central noradrenergic system

We investigated the involvement of brain cytokines and central monoamines in mediating the effect of the neurotropic herpes simplex virus-1 (HSV-1) on adrenocortical activity in rats. Corneal inoculation with a neurovirulent HSV-1 strain, but not with an avirulent strain, induced interleukin-1 beta (IL-1 beta) gene expression mainly in the pons and hypothalamus, and caused an elevation in serum corticosterone levels. Infectious virus was isolated in low titres only from the trigeminal ganglia and pons. Viral DNA was detected by PCR in these tissues and in other brain regions. Virus-induced adrenocortical activation was abolished in rats in which hypothalamic norepinephrine (NE) was depleted by 6-hydroxydopamine. Depletion of hypothalamic serotonin by 5,7-dihydroxytryptamine did not prevent adrenocortical activation. These results suggest that central IL-1 and NE are involved in HSV-1 induced adrenocortical activation.