Melatonin action in the mid-brain can regulate forebrain dop amine function both behaviourally and biochemically

Weak Magnetic Fields as a Novel Therapeutic Modality in Parkinson's Disease

“…Conversely, in rats, pinealectomy reportedly enhances the emergence of neuroleptic-induced purposeless chewing movements, a motor behavior which is related to increased striatal dopaminergic activity and which is considered an animal model for Tardive dyskinesia (Sandyk & Fisher, 1989). These observations are in accord with the presence of melatonin and its receptors in critical dopaminergic areas such as the substantia nigra, striatum, and nucleus accumbens (Niles et al, 1979;Cardinali et al, 1979;Kopp, et al, 1980;Seguela et al, 1982;Vitte et al, 1988;Laudon et al, 1988) as well as with studies demonstrating that melatonin potently inhibits dopamine release and metabolism in the midbrain, hypothalamus, and retina Zisapel et al, 1982;Dubocovich, 1983;Pierce et al, 1984;Bradbury et al, 1985;Melamed et al, 1986;Nowak, 1987;Nowak, 1988).…”

“…Melatonin, in turn has been shown to affect dopamine-mediated behaviors and neuroendocrine functions in experimental animals (Kovacs et al, 1974;Blask et al, 1980;Golus & King, 1981;Bradbury et al, 1985;Gaffori & Van Ree, 1985) and to inhibit L-dopa-induced dyskinesia in mice (Cotzias et al, 1971). Conversely, in rats, pinealectomy reportedly enhances the emergence of neuroleptic-induced purposeless chewing movements, a motor behavior which is related to increased striatal dopaminergic activity and which is considered an animal model for Tardive dyskinesia (Sandyk & Fisher, 1989).…”

“…The effects of magnetic field stimulation on Parkinsonian symptoms highlight the importance of the pineal gland and melatonin specifically, in the regulation of striatal and mesolimbic dopaminergic functions (Cotzias et al, 1971;Bradbury et al, 1985;Sandyk, 1990). Moreover, since light mimics the effects of magnetic fields with respect to the acute suppression of melatonin secretion (Lewy et al, 1980;Vollrath et al, 1989), the effects of magnetic stimulation on Parkinsonism also may support previous animal experimental studies which demonstrate that environmental light is involved in the regulation of central doparninergic functions (Stevens et al, 1981;Dubocovich, 1983;Melamed et al, 1986;Nowak & Zurawska, 1989).…”

Weak Electromagnetic Fields Potentiate the Effects of 4-Aminopyridine in Multiple Sclerosis

“…It is known that the entry of calcium, via voltage-dependent channels, into the nerve terminals acts as a trigger for the synaptic release of neurotransmitters (Miledi, 1973;Reichardt & Kelly, 1983). EMFs also have been shown to alter the circadian secretion of pineal melatonin (Welker et al, 1983;Wilson et al, 1986;Semm, 1983) which, in turn, has been demonstrated to influence the release of neurotransmitter such as dopamine and serotonin (Anton-Tay et al, 1968; Cardinali, 1975;Cardinali et al, 1975;Aldegunde et al, 1985;Zisapel & Laudon, 1983;Bradbury et al, 1985). Furthermore, melatonin influences membrane potential propagation by altering voltage-dependent K+ conductance (Zeise & Semm, 1985).…”

Postpartum Psychosis and the Pineal Gland

“…In fact, animal studies suggest that melatonin is involved in the regulation of the activity of limbic dopaminergic functions (Kovacs et al, 1974;Zisapel et al, 1982;1983;Bradbury et al, 1985), which have been implicated in the pathogenesis of psychosis (MacKay , 1980). Specifically, there is evidence for an antidopamine effect of melatonin since: (a) melatonin inhibits dopamine release in the rat hypothalamus (Zisapel et al, 1982;1983) and rabbit retina (Dubocovic, 1983); (b) melatonin, like dopamine receptor antagonists, increases prolactin release in rats (Martin and Reichlin, 1987) and humans (Webley et al, 1988); (c) melatonin blocks L-dopa induced dyskinesias in mice (Cotzias et al,197 1); (d) melatonin decreases locomotor activity in rats (Bradbury et al, 1985); and (e) pinealectomy is associated with an increased incidence and severity of neuroleptic-induced abnormal perioral movements in rats, a behavior thought to be related to increased dopaminergic activity (Sandyk and Fisher, 1989).…”