Serotonin and melatonin in the iris/ciliary processes and their involvement in intraocular pressure

From the evidence available it is clear that melatonin and serotonin receptors exist in the iris/ciliary processes of the rabbit. These receptors may be involved in maintaining the intraocular pressure (IOP). However, the published results on this point are often contradictory, perhaps because of the variation in the species of animals used and the methodology employed. It is also clear that the data obtained from studies on the rabbit cannot be directly applied to man. Nevertheless, present information points to the possibility that drugs influencing specific serotonin and/or melatonin receptors may be used to influence IOP in man and thus have a therapeutic effect.