INVESTIGADORES
ONS Sheila
artículos
Título:
The effects of chronic food restriction on hypothalamic-pituitary-adrenal activity depend on morning versus evening availability of food
Autor/es:
BELDA XAVIER; ONS SHEILA; CARRASCO JAVIER; ARMARIO ANTONIO
Revista:
PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2005 vol. 81 p. 41 - 46
ISSN:
0091-3057
Resumen:
Partial food restriction (FR) protocols have been used not only to study
behavioral and physiological consequences of decrease food intake, but
as a necessary treatment of the animals in some operant learning tasks.
It is well-established in rodents that restricting food availability to a
few hours in the morning causes an alteration of the daily rhythm of
corticosterone, thus making it difficult to evaluate whether or not such
treatments are stressful. In the present experiment adult male
Sprague-Dawley rats were subjected to two different FR schedules: food
availability after 1100 h (LFR) or after 1900 h (DFR). After 14 days,
animals from both groups, together with corresponding controls, were
killed under resting conditions, either in the morning or in the
evening, just before daily access to food in FR rats. Both FR schedules
reduced body weight gain to the same extent, but their impact on the
hypothalamic-pituitary-adrenal (HPA) axis was different: DFR increased
relative, but not absolute, adrenal weight and morning and evening
levels of corticosterone, whereas LFR increased both absolute and
relative adrenal weights and increased morning corticosterone levels to a
greater extent than DFR rats. Neither serum ACTH nor
corticotropin-releasing factor (CRF) mRNA levels in the paraventricular
nucleus of the hypothalamus were altered by DFR or LFR protocols,
suggesting that factors other than CRF and ACTH are involved in the
control of adrenocortical secretion under FR. It appears that LFR caused
more alterations in the HPA axis than DFR and, therefore, the latter FR
schedule should be used in those protocols necessarily involving
partial FR.