Resumo

Objectives: Recent studies have shown that Angiotensin IV (VYIHPF), a metabolite from renin-angiotensin system (RAS), prolongs the long term potential (LTP) (Brain Res. 897, 114-121) and also facilitates memory (Neuroscience 124, 341-349). One of the possible mechanisms for this facilitation of memory is the inhibition of the insulin-regulated aminopeptidase (IRAP, E.C.3.4.11.3) by Ang IV. IRAP is an aminopeptidase co-localized with the glucose transporter (GLUT) 4 in synaptic vesicles, mainly localized on the hippocampus. (J. Neurochem. 86, 344-350). Also known as ocytocinase, the IRAP is responsible for the degradation of a large number of neuropeptides, as ocytocin, vasopressin and somatostatin (Am. J. Physiol Endocrinol Metab 272, E600-E606). The objectives of this study are: 1) To analyze and quantify the gene expression of IRAP, GLUT 4 and GLUT3 in models of paradoxical sleep deprivation and relate to the learning and memory impairment observed in this model; 2) Compare the enzymatic activity between groups. Methods: Adults male Wistar rats (3 months) were separated into 2 groups: 1) Animals deprived of paradoxical sleep for 96h, using the platform method; 2) Animals restricted of paradoxal sleep for 18h during 15 days, also using the platform method. In both cases a control animal group was used to comparative analysis using the platform method. After the deprivation, the animals were euthanized, had the hippocampus removed and gene expression was quantified by RT-PCR, using the ƒÀ-actine gene as an endogenous control (F: 5�L-AGGCCAACCGTGAAAAGATG-3�L; R: 5�L-CCAGAGGCATACAGGGACAAC-3�L) (BMC Mol. Bio., 10, 45). The experimental protocol has the approval of the Ethical Committee of UNIFESP (CEP N. 0144/09). Results: The validation of IRAP (F: 5�L-GCTTACGTTCCGAGAAGAGAC-3�L; R: 5�L-TTAGCCACAGGTCATTCCAC-3�L), GLUT 3(F: 5�L-AGGATGTCACAGGAGAAGCA-3�L; R: 5�L-GCATTGATCCCAGAGAACTG-3�L) and GLUT 4 (F: 5�L-CTACCCTTTGGGCTCTCTCC-3�L; R: CCAGCATAGCCCTTTTCCTT-3�L), primers was done successfully, with no dymer formation observed. Using these primers, the relative mRNA quantification in paradoxical sleep deprived animals remained unaltered when compared to control animals, the restricted of paradoxal sleep for 15 days remained unaltered for IRAP. Conclusion: Although there is a deficit of memory in sleep deprivation, there is no alteration of the gene expression of these proteins. The next steps will be to measure IRAP�fs activity, quantify the proteins of control and deprived animals, through Western Blot method, and correlate it with the memory deficit.