EFFECT OF A BETA-ADRENERGIC ANTAGONIST, PROPRANOLOL, ON INDUCED HSV-1OCULAR RECURRENCE IN LATENTLY INFECTED-RABBITS

Purpose. Propranolol, a beta-adrenergic antagonist, has been shown to block hyperthermically-induced ocular recurrence of HSV-1 in mice and reduce spontaneous ocular viral shedding and herpetic corneal lesions in latently infected rabbits. The present study was performed to deter mine the effect of propranolol on epinephrine iontophoresis-induced oc ular recurrence and immunosuppression-induced ocular recurrence in the rabbit eye model. Methods. New Zealand white rabbits were infected wi th HSV-1 strain 17Syn(+) or McKrae. After latency was established, the animals were injected intramuscularly with saline (placebo), or propr anolol (5-200 mg/kg) twice daily, and then induced with epinephrine io ntophoresis or cyclophosphamide and dexamethasone administration. Tear film swabs were cultured to determine the frequency of viral shedding . Results. Propranolol administered at a range of doses did not affect the frequency or duration of viral shedding following epinephrine or cyclophosphamide/dexamethasone induction as compared to saline treatme nt. Conclusion. These results demonstrate that propranolol does not si gnificantly reduce ocular HSV-1 shedding following induction by epinep hrine iontophoresis or immunosuppression. By inference, these results suggest two possibilities: (1) that viral pathways leading to spontane ous and induced shedding of virus are under separate control mechanism s or (2) in rabbits, these inducers are of such potency that propranol ol is ineffectual.