Glycine‐immunoreactive neurons in the brain of a shark (Scyliorhinus canicula L.)

Abstract

The glycinergic cell populations in the brain of the lesser spotted dogfish were studied by a glycine immunofluorescence method. Numerous glycine-immunoreactive (Gly-ir) neurons were observed in different brain nuclei. In the telencephalon, Gly-ir cells were observed in the olfactory bulb, telencephalic hemispheres, and preoptic region. In the hypothalamus, cerebrospinal fluid-contacting Gly-ir neurons were observed in the lateral and posterior recess nuclei. Coronet cells of the saccus vasculosus were Gly-ir. In the diencephalon, Gly-ir neurons were observed in the prethalamus and pretectum. In the midbrain, both the optic tectum and lateral mesencephalic nucleus contained numerous Gly-ir neurons. In the cerebellum, many Golgi cells were Gly-ir. In the rhombencephalon, Gly-ir cells were observed in the medial and ventral octavolateral nuclei, vagal lobe, visceromotor nuclei, and reticular formation, including the inferior raphe nucleus. In the spinal cord, some neurons of the marginal nucleus and some cells of the dorsal and ventral horns were Gly-ir. Comparison of dogfish Gly-ir cell populations with those reported for the sea lamprey, Siberian sturgeon, and zebrafish revealed some shared features but also notable differences. For example, Gly-ir cells were observed in the dogfish cerebellum, unlike the case in the Siberian sturgeon and zebrafish, whereas the absence of Gly-ir neurons in the isthmus is shared by all these species, except for lampreys. Gly-ir populations in the dogfish hypothalamus and telencephalon are notable in comparison with those of the other jawed vertebrates investigated to date. Together, these results reveal a complex and divergent evolution of glycinergic systems in the major groups of fishes.

Gustatory and general visceral centers and their connections in the brain of adult zebrafish: a carbocyanine dye tract‐tracing study

“…The primary sensory projections of the glossopharyngeal and vagal nerves on this column have been studied experimentally in a ray (Barry, 1987). Immunohistochemical studies in a dogfish indicate that the vagal lobe contains neurochemically heterogeneous neuronal populations (Carrera et al, 2005(Carrera et al, , 2012Anad on et al, 2013), similar to teleost taste centers, but their projections have not been investigated. In non-teleost actinopterygian fishes, the SGN/V has been reported in sturgeon (Huesa, 2002;Graña et al, 2012) and gar (Grone and Maruska, 2015), and a similar nucleus was observed in cladistians (Graña et al, 2013).…”

Comparative expression patterns of Sox2 and Sox19 genes in the forebrain of developing and adult turbot (Scophthalmus maximus)

“…As a further specificity control, the antiserum to BLBP was tested by western blotting with protein extracts from adult turbot brain. Protein extraction and blotting were performed by standard procedures (for details see Adrio, Rodríguez‐Moldes, & Anadón, ; Anadón, Rodríguez‐Moldes, & Adrio, ). In these blots, the BLBP antibody (Millipore, dilution 1:1,000) stained a single protein band of about 14–15 kDa (Figure ).…”

Morphogenesis of the saccus vasculosus of turbot Scophthalmus maximus: assessment of cell proliferation and distribution of parvalbumin and calretinin during ontogeny

“…They appear to have a glial nature, as they express glial fibrillary acidic protein (GFAP) and vimentin (Arochena et al , ; Sueiro et al , ). Other evidence, however, has demonstrated that they contain glycine (Adrio et al , ; Anadón et al , ), a neuroactive substance classically associated to neurons. Coronet cells could be involved in sensory (Van de Kamer & Schuurmans, ) and secretory (Sundararaj & Prasad, ; Von Mecklenburg, ) activities, as well as in sustaining homeostatic functions (Jansen et al , ) favoured by the absence of a blood–brain barrier in the SV (Jansen & Flight, ).…”