Changes in Calbindin-Containing Neurons in the Dorsal Horn of the Mouse Spinal Cord after Space Flight on Biosatellite Bion-M1

Calbindin (CAL)-containing interneurons in the dorsal horn of the spinal cord (SC) in the superior thoracic segments in male C57/BL6 mice kept in conditions of space flight for 30 days ( n = 3) on the biosatellite Bion-M1 (flight group) were studied using immunohistochemical methods and western blotting. The control group consisted of mice ( n = 3) kept in animal-house conditions at the same time. The number of CABcontaining interneurons in plates I and II increased in mice of the flight group. Western blotting data indicated that CAB expression in the spinal cord increased after flight. This finding, like the predominantly nuclear localization of CAB in neurons of plates I–V, the lack of CAB immunoreactivity in interneurons in areas of the medial edge of the dorsal horn, decreases in the mean cross-sectional area of CAB-immunoreactive interneurons in plate II, increases in the mean cross-sectional area of CAB-immunoreactive interneurons in plates III, IV, and V seen in mice of the flight group, provides evidence of imbalance in the calcium buffer system of SC nerve cells. The calcium system of neuronal functional modules of the SC, especially motor modules, evidently undergoes significant changes in conditions of space flight.