FIBROBLAST GROWTH-FACTOR DECREASES LOCOMOTOR-ACTIVITY IN RATS

The spontaneous locomotor behavior of rats receiving subcutaneous admi nistration of either acidic or basic fibroblast growth factors was rec orded in an activity cage. We report that doses between 1 and 100 mu g /kg significantly decreased the horizontal and vertical activity, as w ell as the exploratory and stereotypy behavior of the rats. These effe cts of fibroblast growth factors seem to be specific since (i) they we re cancelled by protein hydrolysis and anti-fibroblast growth factor a ntibodies, (ii) they were unrelated to their hypotensive activity and (iii) they were not attributable to their high structural similarity w ith the cytokine interleukin-1. Thus, fibroblast growth factors did no t show any thermogenic activity, did not affect the hypothalamic outpu t of corticotropin-releasing factor and did not change the plasma leve ls of corticosterone. Pretreatment of the rats with a specific inhibit or of brain nitric oxide synthase prevented the effects of fibroblast growth factors, suggesting the involvement of nitric oxide in these be havioral modifications. Our results contribute to the accumulating evi dence describing non-mitogenic activities of fibroblast growth factors . Copyright (C) 1996 IBRO.