title: Distribution and onset of retinaldehyde dehydrogenase (zRalDH) expression in zebra finch brain: lack of sex difference in HVC and RA at early posthatch ages.
abstract: Using in situ hybridization to detect the expression of the retinoic acid synthesizing enzyme (retinaldehyde dehydrogenase: zRalDH) mRNA, we mapped the distribution of its expression in adult zebra finch brain. In the neural song circuit, strong expression was found in high vocal center (HVC), para-HVC, and at a very low level in the robust nucleus of the arcopallium (RA). The expression in HVC and RA was found in both males and females. Outside of the song system, major areas of expression were in medial nidopallium (N), hyperpallium apicale (HA), mesopallium ventrale (MV), taenial amygdala (TnA), cerebellar Purkinje cells, and nucleus isthmo-opticus (IO). In nestlings, we found zRalDH mRNA expression in HVC and RA as early as posthatch day 4 or 5 (P4-5), although the expression varied among individuals. Thus, retinoic acid synthesis in HVC and RA could participate in song system formation and development. However, we found no sex difference in volume or intensity of zRalDH and androgen receptor (AR) expression in HVC and RA at P11 prior to the development of significant size dimorphisms in these nuclei. The size of HVC in females at P11 defined by zRalDH expression was greater than that in adult females, suggesting that HVC might experience net cell loss between P11 and adulthood.
authors.affiliation: Department of Physiological Science and Laboratory of Neuroendocrinology of the Brain Research Institute, University of California, Los Angeles, 621 Charles E. Young Drive South, Room 4117, 90095-1606, USA. yhkim11@ucla.edu
authors.forename: Yong-Hwan
authors.initials: YH
authors.lastname: Kim
authors.forename: Arthur P
authors.initials: AP
authors.lastname: Arnold
mesh_terms: D000367:Age Factors; D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000033:anatomy & histology / Q000254:growth & development*; D001931:Brain Mapping; D046369:Finches; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D017403:In Situ Hybridization / Q000379:methods; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012727:Sex Characteristics; D014828:Vocalization, Animal / Q000502:physiology
chemical_list: D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C413419:zRalDH protein, Taeniopygia guttata; D000444:Aldehyde Dehydrogenase