Vol. 275, Issue 6, R2081-R2084, December 1998
RAPID COMMUNICATION
Leptin acts in the rat hypothalamic paraventricular nucleus to
induce gastric mucosal damage
Pauline M.
Smith,
Veronique
Mollaret, and
Alastair V.
Ferguson
Department of Physiology, Queen's University, Kingston, Ontario,
Canada K7L 3N6
Leptin is produced and secreted by
adipocytes to regulate body weight homeostasis. Leptin acts centrally
to reduce weight by decreasing food intake and increasing energy
expenditure. The paraventricular nucleus (PVN) is a central nervous
system structure suggested as a site at which leptin acts to exert its
central effects. Leptin microinjection
(10
6 M, 0.5 µl) into the
PVN of urethan-anesthetized male Sprague-Dawley rats (150-300 g)
resulted in significant gastric damage (mean score = 1.75, n = 16). Damage scores were
significantly different than those observed after saline microinjection
into the PVN (mean score = 0.00, n = 5, P < 0.05), or leptin
microinjection into non-PVN sites (mean score = 0.33, n = 6, P < 0.05). There were no changes in
blood pressure (mean area under curve = 401.9 ± 224.2 mmHg * s,
n = 11, P > 0.05) or heart rate (mean area
under curve = 40.9 ± 25.9 beats, n = 10, P > 0.05) in response to
leptin microinjection into PVN. These results suggest that leptin acts on a functionally specific population of PVN neurons involved in the
control of gastrointestinal function.
gastric mucosa; ulceration
