Melatonin affects the temporal organization of the song of the zebra finch.
In birds and mammals, including humans, melatonin-binding sites are abundant in brain areas that have no known clock function. Although the role of such binding sites is still unclear, it is assumed that these sites link neural functions to circadian or circannual demands of neuroendocrine homeostasis and reproduction. To investigate a possible direct role of melatonin in motor control, we studied the song and neural song system of the zebra finch. Neurons of two sensory-motor areas of the descending song control circuit that are crucial for the organization of the song pattern, the HVC and RA, express the melatonin-1B receptor (Mel1B), while the hypoglossal motor neurons of the song circuit express melatonin-1C receptors (Mel1C). Application of melatonin to brain slices decreases the firing-rate of RA-neurons. Systemic administration of a Mel1B antagonist at the beginning of the night shortens the song and motif length and affects the song syllable lengths produced the next day. The temporal pattern of the song, however, does not undergo daily changes. Thus, melatonin is likely to affect a non-circadian motor pattern by local modulation of song control neurons and in consequence alters a sexual signal, the song of the zebra finch.
Jansen
Rene
R
Department of Developmental and Behavioural Neuroscience, Institute of Neuroscience, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
Metzdorf
Reinhold
R
van der Roest
Marcel
M
Fusani
Leonida
L
ter Maat
Andries
A
Gahr
Manfred
M
D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000502:physiology; D001923:Brain Chemistry; D002645:Chickens; D002940:Circadian Rhythm / Q000187:drug effects*; D003001:Cloning, Molecular; D003342:Corpus Striatum / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D004247:DNA / Q000737:chemistry; D046369:Finches / Q000502:physiology*; D006801:Humans; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D009474:Neurons / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D044123:Receptor, Melatonin, MT2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D044094:Receptors, Melatonin / Q000032:analysis / Q000235:genetics; D017385:Sequence Homology; D014828:Vocalization, Animal / Q000187:drug effects* / Q000502:physiology
D012333:RNA, Messenger; D044123:Receptor, Melatonin, MT2; D044094:Receptors, Melatonin; D004247:DNA; D008550:Melatonin