Effects of leptin on spinally projecting neurons in the PVN of the hypothalamus

The study examined whether intravenous (i.v.) leptin increased Fos-producti on in spinally projecting neurons in the hypothalamic paraventricular nucle us (PVN). We combined (i) rhodamine tagged microspheres injected into the u pper thoracic spinal cord and (ii) Fos (marker of neuronal activation) immu nohistochemistry. Effects of recombinant murine leptin were compared to veh icle (containing lipopolysaccharide a contaminant present in the leptin sol ution). Following leptin, 10% of the spinally projecting neurons contained Fos. However, vehicle elicited similar effects and there was no significant difference between the groups. (C) 1999 Elsevier Science B.V. All rights r eserved.