Calcium Binding Protein Immunoreactivity in Nucleus Rotundus in a Reptile, <i>Caiman crocodilus</i>

Abstract

Nucleus rotundus is a prominent nucleus in the dorsal thalamus of nonmammalian amniotes. In one group of reptiles, Caiman crocodilus, previous studies have identified three parts of this neuronal aggregate. The central portion, the rotundal core, which receives visual input from the midbrain and projects to a restricted portion of the telencephalon, contains relay cells only. Previous examinations using Nissl morphology indicated that neurons of the rotundal core were not a homogeneous population of cells. The present investigation utilized another methodology to examine cell populations within the rotundal core, immunoreactivity to the calcium binding proteins, calbindin/calretinin and parvalbumin. Light microscopic observations revealed the following features. First, calbindin/calretinin immunoreactive neurons and parvalbumin immunoreactive neurons were present in the rotundal core. Of these two antibodies, immunoreactivity to calbindin/calretinin was much more robust and calbindin/calretinin immunoreactive neurons were more numerous than parvalbumin cells. Second, neurons immunoreactive to either calbindin/calretinin or parvalbumin were not homogeneous but comprised several populations based on perikaryal shape and size and neuronal process morphology. These results are compared with similar data in other amniotes.

Thalamic Reticular Nucleus in <b><i>Caiman crocodilus</i></b>: Immunohistochemical Staining

“…Unbiased sampling in these circumstances would have measured even fewer cells and would have been unlikely to produce more meaningful data. Second, unlike previous stereological studies [Pritz, 1997;Pritz and Siadati, 1999], the borders of individual parts of the thalamic reticular nucleus were not as sharply defined as was the case for nucleus rotundus. Lastly, in cases where counted neurons were numerous, PV immunopositive cells of the caudal pole and both GAD(+) and PV(+) cells in the rostral and caudal dorsal peduncu- lar nucleus and associated perireticular area, a decision was made before measurements were undertaken as to how many cells would be measured.…”

“…In previous immunohistochemical studies [e.g., Pritz and Siadati, 1999] identification of neuronal groups was straight-forward and counterstaining was not routinely done. For this reason, none of the immunohistochemical material in this study was counterstained for cell groups.…”

Localization of Calbindin-D28k and Calretinin in the Brain of Dermophis Mexicanus (Amphibia: Gymnophiona) and Its Bearing on the Interpretation of Newly Recognized Neuroanatomical Regions

“…However the different immunostaining allows (in most cases) clear distinction between prethalamus (p3), thalamus (p2), and pretectum (p1), as well as subdivisions within them, that respect and are well explained by the prosomeric model [Pombal and Puelles, 1999;Dávila et al, 2000;Milán and Puelles, 2000;Castro et al, 2006;Morona and González, 2008]. A main trait of the distribution of these proteins in the diencephalon is the abundant presence of CR in thalamic neurons in anamniotes [present results;Pombal and Puelles, 1999;Díaz-Regueira and Anadón, 2000;Milán and Puelles, 2000;Castro et al, 2006], whereas in amniotes CB prevails in the thalamus [Braun, 1990;Pritz and Stritzel, 1991;Pritz and Siadati, 1999;Dávila et al, 2000;Münkle et al, 2000;. Within the alar part of p1, the distribution of CB and CR in Dermophis seemed to match well with the 3 molecularly distinct anteroposterior domains already recognized in several vertebrate groups [Pombal and Puelles, 1999;Dávila et al, 2000;Milán and Puelles, 2000;Ferrán et al, 2007;Morona et al, 2011].…”

Immunohistochemical Localization of Calbindin-D28k and Calretinin in the Spinal Cord of Lungfishes

“…The actual proteins CB and CR have not been isolated in lungfishes, but the Western blot analysis we performed and previously published data suggest that these proteins are conserved in evolution [Wassermann and Taylor, 1966;Parmentier et al, 1987;Denizot et al, 1988] and that the use of antibodies against mammalian or avian proteins is therefore a valuable tool for identifying CBir and CRir structures in the nervous system of a wide variety of vertebrates [Martínez-Guijarro and Freund, 1992;Guirado et al, 1999;Pritz and Siadati, 1999;Cuenca et al, 2000;Dávila et al, 2000;Hackney et al, 2003;Megías et al, 2003;Bennis et al, 2005;González, 2008, 2009]. Furthermore, the present results show that the antibodies used in our analysis of the spinal cord of P. dolloi and N. forsteri yield specific immunostaining and that the simultaneous double-labeling experiments corroborate the lack of cross-reactivity in the case of lungfishes.…”