1. Departments of Pediatrics, Ophthalmology and Pharmacology, Research Center, Hôpital Sainte-Justine, Montreal, Quebec H3T 1C5; Departments of
2. Pharmacology and Therapeutics and
3. Ophthalmology, McGill University, Montreal, Quebec, Canada H3G 1Y6; and
4. Departments of Pharmacology and Medicine, Vanderbilt University, Nashville, Tennessee 37232-6602