Peripheral adrenergic stimulation and indomethacin in experimental ocular shedding of HSV

The application of 6-hydroxydopamine to the cornea by iontophoresis, followed by topical epinephrine, effectively induces herpes simplex virus (HSV) shedding from the external eye of latently infected rabbits. In this study the beta adrenergic blocker, Timolol, reduced virus shedding when applied immediately before the epinephrine, but continued administration resulted in increased viral shedding. While indomethacin, a prostaglandin synthesis inhibitor decreased HSV replication in cell culture, it failed to decrease virus shedding when applied topically to the eye in adrenergically stimulated animals. Timolol may act then by its effect on the peripheral cells of the eye rather than by stimulation of virus production in ganglionic neurons. These same animals were subsequently tested for latent infection of the trigeminal and superior cervical ganglia and corneas 14 months after primary infection. Only 2 of 14 animals had virus in the trigeminal ganglia, a finding which suggests that latent virus may be depleted by repeated reactivations. Virus was recovered from corneas of five rabbits by co-cultivation so it is possible that corneal latency occurs in this rabbit model as it does in humans.