RT info:eu-repo/semantics/article
T1 A vitamin A- free diet results in impairment of the rat hippocampal somatostatinergic system
A1 Hernánez Pinto, Alberto Miguel
A1 Puebla Jiménez, Lilian
A1 Arilla Ferreiro, Eduardo
K1 Retinoic acid
K1 Retinoids
K1 Somatostatin
K1 Hippocampus
K1 Bioquímica
K1 Biochemistry
K1 Science
K1 Ciencia
AB Previous studies have revealed the presence of retinoid specific receptors in the hippocampus and have demonstrated that vitamin A deficiency produces a severe deficit in spatial learning and memory which are linked to a proper hippocampal functioning. It is also well known that the tetradecapeptide somatostatin binds to specific receptors in the hippocampus and, when injected into this brain area, facilitates the acquisition of spatial tasks. In addition, depletion of somatostatin by cysteamine impairs acquisition of these tasks. Taken together, these studies support the idea that the hippocampal somatostatinergic system might be regulated by vitamin A. Hence, we evaluated the effects of vitamin A deprivation and subsequent administration of vitamin A on the rat hippocampal somatostatinergic system. Rats fed a vitamin A-free diet exhibited a significant reduction of somatostatin-like immunoreactivity content in the hippocampus whereas the somatostatin mRNA levels were unaltered. Vitamin A deficiency increased the somatostatin receptor density and its dissociation constant. Functional Gi activity as well as the capacity of somatostatin to inhibit basal and forskolin-stimulated adenylyl cyclase activity was decreased in vitamin A deficiency rats as compared with the control animals. All these parameters were fully restored when vitamin A was replaced in the diet. Furthermore, we found that the Gi alpha(1), Gi alpha(2) and Gi alpha(3) protein levels were unaltered in hippocampal membranes from rats fed a vitamin A-free diet whereas subsequent vitamin A administration to these rats caused a significant increase in the levels of Gi alpha(1) and Gi alpha 2. Altogether, the present findings suggest that dietary vitamin A levels modulate the somatostatinergic system in the rat hippocampus.
PB Elsevier
SN 0306-4522
YR 2006
FD 2006
LK http://hdl.handle.net/10017/2297
UL http://hdl.handle.net/10017/2297
LA eng
NO This work was supported by a grant(SAF 2003-08052) from the Dirección General de Investigacióndel Ministerio de Ciencia y Tecnología of Spain.
DS MINDS@UW
RD 19-abr-2024