title: Illumination controls differentiation of dopamine neurons regulating behaviour.
abstract: Specification of the appropriate neurotransmitter is a crucial step in neuronal differentiation because it enables signalling among populations of neurons. Experimental manipulations demonstrate that both autonomous and activity-dependent genetic programs contribute to this process during development, but whether natural environmental stimuli specify transmitter expression in a neuronal population is unknown. We investigated neurons of the ventral suprachiasmatic nucleus that regulate neuroendocrine pituitary function in response to light in teleosts, amphibia and primates. Here we show that altering light exposure, which changes the sensory input to the circuit controlling adaptation of skin pigmentation to background, changes the number of neurons expressing dopamine in larvae of the amphibian Xenopus laevis in a circuit-specific and activity-dependent manner. Neurons newly expressing dopamine then regulate changes in camouflage colouration in response to illumination. Thus, physiological activity alters the numbers of behaviourally relevant amine-transmitter-expressing neurons in the brain at postembryonic stages of development. The results may be pertinent to changes in cognitive states that are regulated by biogenic amines.
authors.affiliation: Neurobiology Section, Division of Biological Sciences and Center for Molecular Genetics, Kavli Institute for Brain and Mind, UCSD La Jolla, California 92093-0357, USA. ddulcis@biomail.ucsd.edu
authors.forename: Davide
authors.initials: D
authors.lastname: Dulcis
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Spitzer
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology / Q000528:radiation effects*; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects*; D002614:Chelating Agents / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D007814:Larva / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D008027:Light; D008029:Lighting; D052717:Melanotrophs / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects*; D009478:Neuropeptide Y / Q000378:metabolism; D010775:Photic Stimulation; D012880:Skin Pigmentation / Q000502:physiology; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013493:Suprachiasmatic Nucleus / Q000166:cytology / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology; D014982:Xenopus laevis / Q000378:metabolism / Q000502:physiology*
chemical_list: D002614:Chelating Agents; D009478:Neuropeptide Y; D026941:Sodium Channel Blockers; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D013779:Tetrodotoxin; D004533:Egtazic Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D004298:Dopamine