Thy-1-mediated regulation of a low-threshold transient calcium current in cultured sensory neurons.

The physiological effect of ligand binding to the Thy-1 molecule expressed on the neuronal cell surface was examined. Sensory neurons obtained from dorsal root ganglia of 2-day-old CBA/CAH mice (Thy-1.2) were cultured in vitro for 8 days, and then patch-clamp recordings were obtained of calcium currents. It was found that binding of an anti-Thy-1.2 monoclonal antibody to neurons expressing the Thy-1.2 moiety increased the amplitude of a low-threshold transient calcium current. Monoclonal antibodies directed against the Thy-1.1 molecule or a neuronal surface ganglioside (A2B5) had no effect on this calcium current in Thy-1.2-bearing cells, nor did they interfere with subsequent activation by the anti-Thy-1.2 monoclonal antibody. These results demonstrate that ligand binding to the Thy-1 molecule transduces a physiological signal in sensory neurons by increasing a voltage-activated calcium current.