The calcium binding proteins calbindin, parvalbumin, and calretinin have specific patterns of expression in the gray matter of cat spinal cord

Abstract

Calcium binding proteins (CBPs) regulate intracellular levels of calcium (Ca(2+)) ions. CBPs are particularly interesting from a morphological standpoint, because they are differentially expressed in certain sub-populations of cells in the nervous system of various species of vertebrate animals. However, knowledge on the cellular regulation governing such cell-specific CBP expression is still incomplete. In this work on the L7 segment of the cat spinal cord, we analyzed the localization and morphology of neurons expressing the CBPs calbindin-28 KD (CB), parvalbumin (PV), and calretinin (CR), and co-expressing CB and PV, CB and CR, and PV and CR. Single CBP-positive ((+)) neurons showed specific distributions: (1) CB was present in small neurons localized in laminae I, II, III and X, in small to medium size neurons in laminae III-VI, and in medium to large neurons in laminae VI-VIII; (2) PV was present in small size neurons in laminae III and IV and in medial portions of laminae V and VI, medium neurons and in lamina X at the border with lamina VII, in medium to large neurons in laminae VII and VIII; (3) CR labeling was detected in small size neurons in laminae I, II, III and VIII, in medium to large size neurons in laminae I and III-VII, and in small to medium size neurons in lamina X. Double labeled neurons were a small minority of the CBP(+) cells. Co-expression of CB and PV was seen in 1 to 2% of the CBP(+) cells, and they were detected in the ventral and intermediate portions of lamina VII and in lamina X. Co-localization of CB and CR was present in 0.3% of the cells and these cells were localized in lamina II. Double labeling for PV and CR occurred in 6% of the cells, and the cells were localized in ventral part of lamina VII and in lamina VIII. Overall, these results revealed distinct and reproducible patterns of localization of the neurons expressing single CBPs and co-expressing two of them. Distinct differences of CBP expression between cat and other species are discussed. Possible relations between the cat L7 neurons expressing different CBPs with the neurons previously analyzed in cat and other animals are suggested.

Activity-Dependent Codevelopment of the Corticospinal System and Target Interneurons in the Cervical Spinal Cord

“…We used immunohistochemistry to visualize the distribution of cells containing choline acetyltransferase (ChAT), calbindin (CB), parvalbumin (PV), and calretinin (CR), as others have used in cat, rat, and mouse spinal cord Gibson et al, 2000;Clowry et al, 2004;Anelli and Heckman, 2005). ChAT-positive interneurons are implicated in locomotor control (Huang et al, 2000).…”

“…Nothing is known about development of CST projections to identified spinal neuron populations, apart from development of direct projections to motor pools in rhesus monkeys (Armand et al, 1997). We used choline acetyltransferase (ChAT) and calcium-binding protein (CBP) immunohistochemistry in kittens to mark spinal interneurons (Huang et al, 2000;Anelli and Heckman, 2005;Gonzalez-Forero et al, 2005).…”

Distribución de calbindina y parvoalbúmina y efecto del virus de la rabia sobre su expresión en la médula espinal de ratones

“…En nuestro estudio del asta dorsal de ratón, las láminas I y II son las que presentan mayor inmunorreacción de CB y, ocasionalmente, se observan neuronas positivas en la III; esto es similar a lo hallado en otras especies (8,(20)(21)(22). Sin embargo, al evaluar la presencia de células positivas para PV en el asta dorsal del ratón, se observó marcación en las láminas I y II, lo que no concuerda con los reportes previos en ratas y otros mamíferos, ya que se ha descrito su presencia sólo en la margen inferior de la lámina II y, por lo general, no se reporta su inmunorreacción en la lámina I (8,(20)(21)(22)(23)(24).…”

“…Sin embargo, al evaluar la presencia de células positivas para PV en el asta dorsal del ratón, se observó marcación en las láminas I y II, lo que no concuerda con los reportes previos en ratas y otros mamíferos, ya que se ha descrito su presencia sólo en la margen inferior de la lámina II y, por lo general, no se reporta su inmunorreacción en la lámina I (8,(20)(21)(22)(23)(24). Estas diferencias específicas para las especies en la distribución de proteínas como la PV, se han reportado anteriormente en otras áreas del sistema nervioso de los mamíferos (25).…”

“…El conocimiento de la localización, expresión y mecanismo de acción de estas proteínas, ha sido importante en estudios histológicos, inmunohistoquímicos e histopatológicos del sistema nervioso, ya que se expresan diferencialmente en determinadas subpoblaciones neuronales. Su utilidad se ha demostrado en diversas especies de vertebrados, especialmente en mamíferos (8)(9)(10)(11).…”