Changes in platelet count and related parameters in SART-stressed mice and the action of administered neurotropin

In order to hematologically characterize SART-stressed (repeated cold-stressed) animals, which are regarded as model animals of clinical dysautonomia, general hematological analyses were performed in mice subjected to various types of stress. SART-stressed mice showed significant increases in erythrocyte count, hemoglobin, hematocrit and specific gravity of whole blood, no change in leukocyte count and a marked decrease in platelet count. Among the above changes, the decreased platelet count was particularly characteristic of SART-stressed mice. Splenectomy failed to inhibit the SART stress-induced thrombocytopenia. Bone marrow megakaryocyte counts increased following the stress. The bleeding time of SART-stressed mice was more than double that of normal mice. Consecutive administrations of Neurotropin, a sedative analgesic, completely blocked the alterations in platelet count, megakaryocyte count and bleeding time in SART-stressed mice without producing any effect in unstressed mice. From the present results, it is suggested that SART-stressed mice may be characterized by thrombocytopenia, which is not attributable to enhanced function of the spleen or suppressed platelet production in the bone marrow. Moreover, Neurotropin appears to be effective for moderating SART stress.