The organization of monoamine‐containing neurons in the brain of the sunfish (Lepomis gibbosus) as revealed by fluorescence microscopy

Abstract

The morphological organization of the monoamine-containing neurons in the brain of the sunfish (Lepomis gibbosus) was studied by means of the Falck-Hillarp histofluorescence method. No attempt was made to distinguish between norepinephrine and dopamine, both primary catecholamines (CA) yielding a similar yellow-green fluorescence after paraformaldehyde treatment. In the brain stem of this teleost fish, three groups of CA-containing neuronal somata have been found. First, there is a small collection of CA perikarya located just caudal to the obex of the fourth ventricle. The neurons of this medullo-spinal group give rise to numerous CA fibers many of which ascend within the central portion of the medulla. Intermingled with these CA fibers are some CA cells that constitute the cendral medullary group. The CA perikarya of this group are scattered between the levels of cranial nerves X and VIII. The tegmentum of the isthmus also contains a small group of very closely packed CA neurons. The large-sized CA cells of the isthmal group are located dorsolateral to the medial longitudinal fasciculus, partly within the periventricular gray. High densities of CA varicosities were also disclosed in various brain stem structures such as the optic tectum, the torus semicircularis and the cerebellar valvula. In addition, numerous serotonin (5-HTI-type neuronal somata were found in the raphe region of the brain stem, particularly a t caudal mesencephalic, isthmal and rostra1 medullary levels.A large number of CA cell bodies were visualized in the sunfish hypothalamus. Most of them form two populations of small, round cells that are located along and partly within the ependymal walls of the posterior and lateral recesses of the third ventricle. These bipolar cells possess one short club-like process protruding into the ventricle and their thin ependymofugal processes contribute to the CA innervation of numerous hypothalamic regions. Large CA neurons apparently without direct CSF contact also occur in the area of nucleus posterior tuberis, a t the level of the mesodiencephalic junction. Although the hypothalamic inferior lobes are devoid of CA cell bodies they are heavily innervated by CA axons.The sunfish telencephalon also receives a strikingly massive and complex monoaminergic innervation. Numerous CA fibers which are first observed a t the level of the preoptic area, ascend through the central zone of the telencephalon and arborize profusely particularly within the medial zone of area dorsalis telencephali. Other CA fibers, as well a s abundant fine 5-HT varicosities were found in the lateral zone of area dorsalis. Although the exact origin of the telencephalic CA afferents in Lepomis is not known, part of it may arise from the isthmal CA cell group which appears similar to the locus coeruleus of reptiles, birds and mammals. ' Reprint requests should be sent t o Dr. A, Parent,

Tyrosine Hydroxylase Immunoreactivity in a Subpopulation of Granule Cells in the Olfactory Bulb of Teleost Fish

“…However, it is very difficult to generalize, as other cartilaginous fish such as Raja radiaia [33] show a considerable number of moderately stained dopaminergic neurons lying around the glomeruli, a situation strikingly similar to that found in amniotes. In teleosts, Parent et al [29] were unable to recognize any fluorescent perikarya but did report positive centrifugal fibers in the olfac tory bulb of the sunfish (Lepomis gibbosus) with the use of the Falck-Hillarp technique. More recently, Yoshida et al [30] and Nagatsu et al [28] have sug gested the presence of a population of TH-positive neurons, at present uncharacterized, in the olfactory bulb of the goldfish Carassius auralus.…”

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

“…Immunohistochemical studies in Polypterus [Reiner and Northcutt, 1992] and teleosts [Sharma et al, 1989;Vecino et al, 1989;Batten et al, 1990] have described SP+ cell bodies and fibers in Vd except in the case of Apteronotus, where SP+ labeled neurons are localized in Vv [Weld and Maler, 1992]. Fibers positive for 5HT and TH and/or DA also characterize Vd [Parent et al, 1978;Parent and Northcutt, 1982;Yoshida et al, 1983;Hornby et al, 1987;Meek andJoosten, 1989, 1993;Roberts et al, 1989;Ekström et al, 1990;Hornby and Piekut, 1990;Johnston et al, 1990;Sas et al, 1990;Holmqvist and Ekström, 1991;Reiner and Northcutt, 1992;Manso et al, 1993;Anadón et al, 2002]. 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].…”

Amygdala and Emotional Learning in Vertebrates – A Comparative Perspective

“…Also, the deficit showed in both the acquisition and retention in avoidance behavior cannot be attributed to the lack of activity or initiative of the animal after lesion, because the level of escape is very high. In addition, the absence of effects on spatial memory or motor response (Portavella & Vargas, 2005) rules out a possible functional homology with the hippocampus and basal ganglia of tetrapods (Braford, 1995;Braford et al, 1992;Echteler & Saidel, 1981;Murakami et al, 1983;Nieuwenhuys & Verrijdt, 1983;Northcutt, 1995;Northcutt & Braford, 1980;Parent, 1986;Parent et al, 1978). Thus, we concluded that the lesion produced a deficit in the associative process between the discriminative stimulus and the shock (Portavella et al, 2002;2004a, 2004bPortavella & Vargas, 2005;Vargas et al, 2009).…”

“…In actinopterygians, the telencephalon undergoes an eversion process that raises a serious difficulty in establishing homologies with the amygdala (Braford, 1995;Gage, 1983;Scalia & Ebbesson, 1971). However, the cytoarchitecture, the neurohistochemistry, studies of embryonic development, the pattern of connectivity and topological studies (Braford, 1995;Chanconie & Clairambault, 1975;Morgan, 1974aMorgan, , 1974bMurakami et al, 1983;Northcutt, 1981;Northcutt & Braford, 1980) suggest that the region Dmv of the teleost telencephalon is a good candidate to be considered the homologue of the pallial amygdala (Northcutt, 1995;Northcutt & Braford, 1980), although other authors suggest that Dmv could be homologous to the basal ganglia or the hippocampus of mammals (Murakami et al, 1983;Parent et al, 1978). Moreover, the pattern of connectivity, with strong sensory thalamic inputs and reciprocal connections with the hypothalamus, gives a distinctly limbic character to Dmv (Braford, 1995;Echteler & Saidel, 1981;Ito et al, 1986;Murakami et al, 1983;Striedter, 1991).…”

“…It is considered that the amygdala is not an exclusive structure of mammals, since genoarchitectonic, neurochemical, embryological, anatomical, and behavioral studies in a comparative perspective (Aggleton, 1992;Bruce & Neary, 1995;Macphail, 1996;Medina et al, 2011;Moreno & González, 2006;Parent, 1986;Sriedter, 1997;Wulliman & Rink, 2002) have proposed several homologies for this structure in other vertebrate groups (fish, amphibians, reptiles, and birds). Although there has been no complete agreement on the homology of all parts of this structure (pallial and subpallial portion) among all vertebrate groups over time (Braford, 1995;Bruce & Neary, 1995;Northcutt, 1995;Sriedter, 1997), the existence of a basic scheme of the amygdala in fish, reptiles, birds, and mammals, irrespective of the diverse differentiation of this structure along the evolution of the different groups of tetrapods has been established by examining the comparative genoarchitecture (Medina et al, 2011;Moreno & González, 2006;.…”