RT info:eu-repo/semantics/article
T1 Activity of the hippocampal somatostatinergic system following daily administration of melatonin
A1 Izquierdo Claros, Rosa María
A1 Boyano Adánez, María del Carmen
A1 Arilla Ferreiro, Eduardo
K1 Somatostatin receptors
K1 Melatonin
K1 Adenylyl cyclase
K1 G proteins
K1 Hippocampus
K1 Rat
K1 Bioquímica
K1 Biochemistry
K1 Science
K1 Ciencia
AB If melatonin or its analogs are to be used therapeutically in humans, their chronic effects on responsiveness of melatonin target cells need to be assessed. We have previously demonstrated that acute melatonin treatment regulates the somatostatinergic system in the rat hippocampus. In the present study, we have investigated the effects of subchronic and chronic daily treatment with melatonin on the somatostatinergic system in the rat hippocampus. Male Wistar rats (200-250 g) were injected with melatonin (25 ¿g/kg body weight, subcutaneously) daily for 4, 7 or 14 days and sacrificed 24 h after the last injection. Melatonin administration for 4 days induced a decrease in the hippocampal somatostatin (SRIF)-like immunoreactivity content as well as a decrease in the number of SRIF receptors and an increase in their apparent affinity. The decreased number of SRIF receptors in the melatonin (4 days)-treated rats was associated with a decreased capacity of SRIF to inhibit both basal and forskolin-stimulated adenylyl cyclase activity. These melatonin-induced effects reversed to control values after 7 or 14 days of treatment. Hippocampal membranes from control and melatonin-treated rats showed similar Gi and Gs activities. Melatonin treatment altered neither the functional Gi activity nor the Gi¿1 or Gi¿2 levels at any of the time periods studied. The present results suggest that chronic exposure to melatonin results in a tolerance of the hippocampus to this hormone.
PB Elsevier
SN 0169-328X
YR 2004
FD 2004
LK http://hdl.handle.net/10017/2259
UL http://hdl.handle.net/10017/2259
LA eng
DS MINDS@UW
RD 02-jun-2023