In conclusion, WARs have a hyperplasic adrenal gland, do not present ACTH circadian cycles and have higher corticosterone levels in response to exogenous ACTH than Wistar controls. These HPA axis abnormalities make WARs a suitable model to study stress and epilepsy as well as epilepsy–neuropsychiatry comorbidities. Male Wistar rats that were not susceptible to audiogenic seizures from

the main breeding colony at the Campus of Ribeirão Preto of the University of São Paulo and males from the WAR strain susceptible to sound-induced seizures (Doretto et al., 2003a) were used in this study. All experimental protocols used in this study were reviewed and approved by the Animal Care and Use Committee of the School of Medicine of Ribeirão Preto of the University of de São Paulo (Protocol number 203/2005). WARs were derived from a check details Wistar strain Ponatinib order of albino rats and have been selected for audiogenic seizure sensitivity (Doretto et al., 2003a) at the Vivarium of the Physiology Department of the Ribeirão Preto School of Medicine at the University of São Paulo. Wistar and WARs

were age-matched (56 to 63 days) and individually housed with free access to standard rat food and water in a controlled environment with a light/dark cycle of 12/12 h (light on at 6 a.m. and light off at 6 p.m.). The animals were allowed to habituate to the room for at least 5 days prior to the studies and were handled and weighed daily in order to reduce stress during the experiments. To determine the animal’s growth, both WARs and Wistar were weighed weekly, from their birth until the 9th week

of age. When animals were 21 days old, they were separated from their mothers and housed in collective cages with free access to food and water. To evaluate the circadian rhythm of corticosterone and ACTH plasma levels and adrenal gland weight, rats were decapitated under basal conditions at 8 a.m. and 8 p.m., and trunk blood samples were used for plasma L-NAME HCl corticosterone and ACTH measurements. In the morning, we also determined the left adrenal gland weight. Groups: Wistar 8 am (n = 6), Wistar 8 pm (n = 6), WAR 8 am (n = 6) and WAR 8 pm (n = 7). To perform the morphometric analysis of adrenal gland, we collected the glands of WAR and Wistar under basal conditions. Adrenal glands were fixed for 24 h in formalin, embedded in paraffin, and serially sectioned at 5 μm. Sections were stained with Gomori’s trichrome by standard protocols and photographed using a Zeiss Axiostar Plus microscope fitted with an Axiovision digital camera (Zeiss, Hemel Hempstead, UK).The area of the cortex was analyzed from digital images using AxiovisionRel4.6 software. The measurement was performed on four adjacent sections from the middle portion of each individual adrenal gland to ensure a reliable comparison. The medullary area and the length of the cortical layers (reticularis, fasciculata and glomerulosa) were measured under standardized conditions.