The distribution of tyrosine hydroxylase immunoreactivity in the brains of male and female zebra finches

Abstract

A system of brain nuclei controls song learning and behavior in zebra finches (Poephila guttata). The size of song-control nuclei are much larger in males, which sing, than in females, which do not sing. This study examined the distribution of fibers, terminals, and cell bodies that are immunoreactive for tyrosine hydroxylase (TH) (the rate-limiting enzyme in the synthesis of catecholamines) in song-control nuclei of adult males and females and juvenile males. In addition, the broad pattern of TH staining throughout the brain was described. There was a sex difference in TH immunoreactivity within song-control nuclei: males had light to moderate staining in all three cortical nuclei examined, whereas females had little or no label in corresponding areas [lateral magnocellular nucleus of the anterior neostriatum (IMAN), higher vocal center (HVC), and robust nucleus of the archistriatum (RA)]. The song-control nucleus area X (X), located in the striatum of avian basal ganglia, was more darkly stained than the surrounding striatum only in males; X was not defined by more intense immunoreactivity in females and hence could not be visualized. There were no apparent differences in TH staining in males ranging in age from 50 days to adulthood (> 90 days). Outside of the song-control system there were no substantive differences as a function of sex or age in the pattern or intensity of TH labeling. Major areas of telencephalic staining included the striatal region of basal ganglia, which was covered with dense, fine-grained label, and the septum, where cell bodies were encircled by extremely well-labeled thick processes. In the diencephalon, the preoptic area and hypothalamus included a complex pattern of darkly stained somata and fiber and terminal labeling. Darkly stained somata surrounded the pretectal nucleus, and labeled processes ramified throughout the superficial layers of the optic tectum. The midbrain and hindbrain contained a dense plexus of extremely dark cell bodies corresponding to mammalian substantia nigra, adjacent tegmental areas, and locus ceruleus. Labeled hindbrain cells were also seen in the pontine region, around nucleus solitarius, and in the ventrolateral medulla.

Revised nomenclature for avian telencephalon and some related brainstem nuclei

“…2E, 5D) and cholinesterase-rich neuropil, and an enrichment in GABAergic neurons that either contain SP/DYN ( Fig. 5A-C) or enkephalin (Lewis et al, 1981;Bottjer, 1993;Casto and Ball, 1994;Grisham and Arnold, 1994;Reiner et al, 1994;Medina and Reiner, 1995;Soha et al, 1996;Reiner et al, 1998a;Luo and Perkel, 1999b;Sun and Reiner, 2000). Additionally, most of the LPO develops from a Dlx1/2-rich and Nkx2.1-poor neuroepithelium ( Fig.…”

“…Diverse lines of evidence indicate that the PA has striatal traits and, together with what has been called the LPO, constitutes the striatal part of avian dorsal basal ganglia (Karten, 1969;Lewis et al, 1981;Bottjer, 1993;Casto and Ball, 1994;Reiner et al, 1994Reiner et al, , 1998aMedina and Reiner, 1995;Soha et al, 1996;Farries and Perkel, 2000;Puelles et al, 2000;Sun and Reiner, 2000). The striatal traits of the PA include a prominent dopaminergic input (Fig.…”

Fos responses of dopamine neurons to sociosexual stimuli in male zebra finches

“…This colocalization decreased in response to all conspecific stimuli except fighting, and did not decrease following exposure to a heterospecific male. Keywords dopamine; forebrain; aggression; sexual behavior; tyrosine hydroxylase; Fos Dopamine (DA) is known to influence a variety of social behaviors, particularly male sexual behavior, in multiple vertebrate groups (Warner et al, 1991;Pomerantz, 1992;Absil et al, 1994;Hull et al, 1995;Dominguez et al, 2001;Woolley et al, 2001;Melis et al, 2003;Charlier et al, 2005), and DA cells are distributed in homologous groups across the vertebrate classes (Bailhache and Balthazart, 1993;Bottjer, 1993;Gonzalez and Smeets, 1994;Reiner et al, 1994;Tillet, 1994;Appeltants et al, 2001;Adrio et al, 2002). This similarity across vertebrates is particularly clear when comparing mammals and birds, which each have dopaminergic neurons (immunopositive for tyrosine hydroxylase, TH, and immunonegative for dopamine β-hydroxylase) localized to eight populations of the basal forebrain and brainstem numbered A8 through A15 (Reiner et al, 1994;Tillet, 1994).…”

Dopaminergic modulation of reproductive behavior and activity in male zebra finches

“…Singing is controlled by a series of well-defined, interconnected nuclei known as the vocal control system [34]. Immunocytochemical studies using antibodies to tyrosine hydroxylase, the rate-limiting enzyme in the synthesis of DA and the other catecholaminergic neurotransmitters, showed the vocal control system is strongly innervated by catecholaminergic neurons [4,14]. Such strong catecholaminergic innervation is not seen in comparable forebrain areas in species of birds that do not sing [7,33].…”

“…The catecholaminergic innervation of the vocal control system is also sexually differentiated in species in which females sing less than males. For example, the catecholaminergic innervation of the vocal control system is much stronger in male zebra finches and canaries than in females [4,14]. When female canaries are treated with testosterone, the frequency and complexity of their singing behavior increases.…”