Distribution of tyrosine hydroxylase (TH) and dopamine β‐hydroxylase (DBH) immunoreactivity in the central nervous system of two chondrostean fishes (Acipenser baeri and Huso huso)

Abstract

To obtain a better understanding of the evolution of the brain catecholaminergic systems of fishes, we have examined the distribution of catecholamine-synthesizing enzymes in two species of sturgeon (Acipenser baeri and Huso huso) using antibodies against tyrosine hydroxylase (TH) and dopamine-beta -hydroxylase (DBH; only analyzed in Acipenser). Both sturgeons showed TH-immunoreactive (THir) neurons widely distributed in most regions of the brain, the highest number of THir cells being located in the forebrain (olfactory bulb, preoptic area, and posterior tuberculum). THir cells were also seen in other forebrain areas (retrobulbar area, dorsal and ventral telencephalic areas, hypothalamus, ventral thalamus, pretectal area) and in the brainstem (locus coeruleus, viscerosensory area, caudal reticular formation, and area postrema). Immunoreactive fibers and varicosities showed a wide distribution, being particularly abundant in the diencephalon and mesencephalon. DBH-immunoreactive (DBHir) cells were observed in the anterior tuberal nucleus, where these cells were TH-negative, and in the locus coeruleus and the caudal rhombencephalon (vagal reticular formation), where the DBHir cells were also THir. DBHir fibers were scarce in the telencephalon and very abundant in the diencephalon, mesencephalon, and rhombencephalon. The comparative analysis of the catecholaminergic systems of chondrosteans and those observed in other groups of fishes and tetrapods indicate a similar organization of many nuclei, as well as characteristics that are probably primitive, such as the presence of a large number of forebrain catecholaminergic groups.

Immunohistochemical Organization of the Forebrain in the White Sturgeon, <i>Acipenser transmontanus</i>

“…In most teleosts, TH-and DAimmunoreactive perikarya are found in similar patterns except in the case of Gnathonemus where differences have been reported Meek and Joosten, 1993]. In Acipenser and Huso [Adrio et al, 2002], TH+ cell bodies are localized in the same telencephalic nuclei as described in teleosts and Polypterus , but the location of DA+ cell bodies is distinct from that of cells labeled for TH. These dopaminergic cells are CSF-contacting, whereas the TH-positive neurons are located more laterally and are quite far from the ventricle.…”

“…In this species, the region of the pallium initially recognized as Dm has a high density of TH+ cells and fibers, whereas only a ventral segment of the area originally recognized as Dp exhibits TH activity. Adrio et al [2002] also described the distribution of TH+ cells in the rostral pallium of the Siberian sturgeon in an area that we recognize as Dm, but these authors apparently failed to detect the more caudal pallial TH population. In contrast to Dm, however, most of Dp is richly innervated by SP+ fibers.…”

“…In 2000, however, Huesa and colleagues experimentally examined secondary olfactory projections in the Siberian sturgeon, Acipenser baeri , and failed to observe secondary olfactory projections to Dp, the largest and densest target of secondary olfactory fibers in the shovelnose sturgeon. Other members of the Santiago de Compostela school accepted the absence of these projections and, consequently, did not recognize Dp or indicate pallial borders in three additional immunohistochemical papers [Adrio et al, 1999[Adrio et al, , 2000[Adrio et al, , 2002. Very recently, however, Huesa et al [2006] reconsidered pallial divisions in the Siberian sturgeon and recognized Dp as a dense band of AChE-positive cells bordered laterally by a neuropil.…”

Stalking the Everted Telencephalon: Comparisons of Forebrain Organization in Basal Ray-Finned Fishes and Teleosts

“…The most salient features reported include: 1) Dm displays a higher number of somata and fibers positive for tyrosine hydroxylase than the rest of the pallium; and 2) the ventral portion of the postcommissural portion of Dp has the highest concentration of fibers positive for substance P in the pallium [Adrio et al, 2002;Piñuela and Northcutt, 2007]. Thus the zone recognized as Dp and in receipt of olfactory projections (see below) displays two different patterns of substance P distribution: precommissural portion, relatively sparse; postcommissural portion, relatively dense.…”

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).…”