ABSTRACT
The retinas of most vertebrate species contain circadian clocks that allow physiological anticipation of daily changes of light intensity as a function of the solar day-night cycle. These clocks regulate light and dark adaptation, turnover of photoreceptor outer segment membranes, gene expression, metabolism, and neurotransmitter release. The goldfish (Carassius auratus) has been an extremely useful model to study circadian mechanisms of adaptation. However, until recently the clock molecules responsible for generating these circadian rhythms in goldfish retina have not been studied. In this chapter we will review studies of circadian regulation of physiology and biochemistry as well as the cloning and rhythmic expression of circadian clock genes in the goldfish retina, with comparisons to other vertebrate species.
