Calcium-binding proteins in the spinal cord: physiological significance

Abstract

There has been increased interest in the presence of calcium-binding proteins (CBPs) in the spinal cord over the past few years (Yamamoto et al., 1989; Antal et al., 1990; Celio, 1990; Yoshida et al., 1990; Zhang et al., 1990; Arvidsson et al., 1992; Menétrey et al., 1992b; Heppelmann and Emson 1993; Ren et al., 1993; Ren and Ruda, 94; also see Andressen et al., 1993, for a review). This interest is partly due to the unique advantage of some CBPs as neuronal markers in the spinal cord. As in other parts of the nervous system, several CBPs exhibit a distinct distribution pattern, suggesting that they may be involved in a variety of physiological activities, including initial sensory processing and final motor control. CBPs not only couple the elevation of intracellular Ca2⁺ in response to an extracellular signal with the subsequent physiological response, they also modulate the intracellular Ca⁺ level to help maintain Ca⁺ homeostasis. The latter action of the CBPs is especially important as the perturbation of the intracellular Ca⁺ homeostasis may precede the development of cytotoxicity and irreversible injury (Nicotera et al., 1992).