Abstract
The eyes of the marine snail Bulla gouldiana act as circadian pacemakers. The eyes exhibit a circadian variation in spontaneous optic nerve compound action potential frequency in constant darkness, and are involved in controlling circadian rhythms in behavioral activity expressed by the animal. To initiate an investigation of the molecular aspects of circadian rhythmicity in the Bulla eye and to identify specific molecular markers in the nervous system, we raised monoclonal antibodies (MAb) to the eye and screened them for specific patterns of staining in the eye and brain. Several MAb recognize antigens specific to groups of neurons in the brain, whereas others stain antigens found only in the eye. In addition, some antigens are shared by the eye and the brain. The antigens described here include molecules that mark the lens, retina, neural pathways between the eye and the brain, specific groups of neurons within the central ganglia, and an antigen that is shared by basal retinal neurons (putative ocular circadian pacemaker cells) and glia. These molecular markers may have utility in identifying functionally related groups of neurons, elucidating molecular specializations of the retina, and highlighting pathways used in transmission of information between the retina and the brain.