Behavioural and EEG effects of chronic rapamycin treatment in a mouse model of Tuberous Sclerosis Complex Marco Cambiaghi a, b,1 , Marco Cursi a, b, c,1 , Laura Magri a, d,1 , Valerio Castoldi a, b , Giancarlo Comi a, b, e , Fabio Minicucci a, c , Rossella Galli a, d , Letizia Leocani a, b, * a San Raffaele Scientific Institute, Milan, Italy b Experimental Neurophysiology Unit, Institute of Experimental Neurology (INSPE), IRRCS University Hospital San Raffaele, Via Olgettina 60, 20132 Milan, Italy c Epilepsy Unit, Department of Neurology, Hospital San Raffaele, Milan, Italy d Neural Stem Cell Biology Unit, Division of Regenerative Medicine, Milan, Italy e University Vita Salute San Raffaele, Milan, Italy article info Article history: Received 10 July 2012 Received in revised form 30 October 2012 Accepted 1 November 2012 Keywords: Tuberous Sclerosis Complex Rapamycin Behaviour EEG Spectral analysis abstract Tuberous Sclerosis Complex (TSC) is a multisystem genetic disorder caused by mutation in either Tsc1 or Tsc2 genes that leads to the hyper activation of the mTOR pathway, a key signalling pathway for synaptic plasticity. TSC is characterized by benign tumors arising in different organs and severe neuropsychiatric symptoms, such as epilepsy, intellectual disability, autism, anxiety and depressive behaviour. Rapamycin is a potent inhibitor of mTOR and its efficacy in treating epilepsy and neurological symptoms remains elusive. In a mouse model in which Tsc1 has been deleted in embryonic telencephalic neural stem cells, we analyzed anxiety- and depression-like behaviour by elevated-plus maze (EPM), open-field test (OFT), forced-swim test (FST) and tail-suspension test (TST), after chronic administration of rapamycin. In addition, spectral analysis of background EEG was performed. Rapamycin-treated mutant mice displayed a reduction in anxiety- and depression-like phenotype, as shown by the EPM/OFT and FST, respectively. These results were inline with EEG power spectra outcomes. The same effects of rapamycin were observed in wild-type mice. Notably, in heterozygous animals we did not observe any EEG and/or behavioural variation after rapamycin treatment. Together these results suggest that both TSC1 deletion and chronic rapamycin treatment might have a role in modulating behaviour and brain activity, and point out to the potential usefulness of background EEG analysis in tracking brain dysfunction in parallel with behavioural testing. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Tuberous Sclerosis Complex (TSC) is an autosomal dominant disorder caused by mutations in either TSC1 (hamartin) or TSC2 (tuberin) genes. The disease is characterized by histologically defined benign lesions, named hamartomas, found in different organ systems such as kidneys, lungs, skin and central nervous system (Crino et al., 2006; Curatolo et al., 2008). In the brain, hamartomatous lesions are strongly associated with neuropsychi- atric symptoms. These are due to specific types of brain structural abnormalities known as cortical tubers (DiMario, 2004; Crino et al., 2006). Accordingly, evidence for a direct role of aberrant molecular pathway activation on neuropsychiatric symptoms in TSC has also been reported (de Vries and Howe, 2007; Ehninger et al., 2008; Goorden et al., 2007). Notably, the tissue surrounding the lesions could also be affected by minor dysplasia (Major et al., 2009). Up to 90% of TSC affected patients suffer from epilepsy and almost 50% from intellectual disability (Joinson et al., 2003). Intelligence quotients (IQ) are distributed bi-modally in TSC patient populations (de Vries and Prather, 2007). Approximately 20e30% of patients have very low IQs and require life-long assistance. About 50% of patients show specific neuropsychological impairments such as Abbreviations: DSA, density spectral array; EEG, electroencephalography; EPM, elevated-plus maze; FFT, Fast Fourier Transform; FST, forced-swim test; MDF, mean dominant frequency; mTOR, mammalian target of rapamycin; OFT, open field test; PND, post-natal day; TSC, Tuberous Sclerosis Complex; TST, tail suspension test. * Corresponding author. Experimental Neurophysiology Unit, Institute of Exper- imental Neurology (INSPE), IRRCS University Hospital San Raffaele, Via Olgettina 60, 20132 Milan, Italy. Tel.: þ39 02 2643 3092; fax: þ39 02 2643 3085. E-mail addresses: cambiaghi.marco@hsr.it (M. Cambiaghi), cursi.marco@hsr.it (M. Cursi), magri.laura@hsr.it (L. Magri), castoldi.valerio@hsr.it (V. Castoldi), comi.giancarlo@hsr.it (G. Comi), minicucci.fabio@hsr.it (F. Minicucci), galli.rossella@hsr.it (R. Galli), letizia.leocani@hsr.it (L. Leocani). 1 These authors equally contributed to this work. Contents lists available at SciVerse ScienceDirect Neuropharmacology journal homepage: www.elsevier.com/locate/neuropharm 0028-3908/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.neuropharm.2012.11.003 Neuropharmacology 67 (2013) 1e7