0 a hormone in the body that produces changes in skin colour and is involved in controlling biorhythms such as our sleep pattern --
Despite this general decrease in dopamine levels, our melatonin-injected mice displayed a clear rhythm of dopamine content.
Indeed, dopamine and melatonin may act as mutually inhibitory retinal signals for day and night.
Additionally, the presence of melatonin receptor protein on putative retinal efferent fibers suggests a role for melatonin in the central control of retinal sensitivity.
The output of the hormone melatonin, implicated in synchronization of the sleep/wake cycle, is frequently impaired in dementia.
There is considerable evidence for functional interactions of melatonin and dopamine in the retina.
A probable explanation for the decrease in dopamine content is an inhibitory effect of melatonin on dopamine synthesis.
The administration of exogenous melatonin has equivocal evidence in the promotion of a healthy sleep cycle and alleviation of behaviour problems.
Figure 4 illustrates the biosynthetic pathway for the synthesis of melatonin from tryptophan.
