Neurodevelopmental psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) occur during adolescence, in which the brain undergoes some major re-organization with regards to anatomy, neuronal morphology and connectivity, receptor expression, and neurotransmitter release. The spontaneously hypertensive rat (SHR) has been established as a valuable model of ADHD^[1,2]. The goal of this study was to investigate differences in the metabolic profile of SHR and Wistar-Kyoto rat (WKY) during adolescence at postnatal day 42. An MR acquisition protocol optimized for 11.7T field-strength was combined with dedicated spectral post-processing algorithms to achieve MR spectra of so far unmet spectral fidelity. In vivo ¹H MR spectra were acquired from the striatum and prefrontal cortex of WKY (N = 7) and SHR rat (N = 6) at postnatal day (P) 42. Experiments were performed at 500 MHz on a 11.7 T horizontal superconducting magnet with 16 cm bore size (117/16 USR BioSpec, AVANCE III, ParaVision 6.01, Bruker BioSpin, Ettlingen, Germany) equipped with a 9 cm inner diameter self-shielded gradient coil insert (Bruker BioSpin, Ettlingen, Germany) capable of supplying up to 750 mTm⁻¹ in 80 μs rise time. A 72 mm birdcage quadrature volume resonator (Bruker) was used for excitation and a receive-only rat brain surface coil array 2x2 (Bruker) was used for signal reception. Volume-of-interests (VOI) were planned based on T2-weighted multi-slice RARE images. Field homogeneity was adjusted individually for each investigated region using MAPSHIM. A short-echo-time STEAM spectroscopy sequence (TR/TE/TM: 5000/3.5/10 ms, 256 acquisitions) combined with VAPOR water suppression was used^[3]. Spectra were acquired from 18.5µl (striatum) and 27.5 μL (prefrontal cortex) volumes. Single-shot data were frequency and phase corrected prior to summation in Matlab^[4]. Unsuppressed water signal was used as an internal reference as well as for eddy current correction. LCModel analysis was performed in the chemical shift range of 0.5–4.2 ppm ^[5]. Representative water-suppressed in vivo proton MR spectra of the investigated rat brain regions clearly show the well-resolved resonances of numerous cerebral metabolites signals (Fig. 1), obtained with sufficiently consistent spectral quality. The average full width at half-maximum found by LCModel was 0.025 ± 0.003 ppm (12.5 ± 1.5 Hz) in the striatum and 0.028 ± 0.002 ppm (14 ± 1Hz) in the prefrontal cortex of rats. Corresponding SNR were 24.9 ± 2.5 and 37.7 ± 3.8. Average cramer rao lower bound (CRLB) for GABA, Glu and Gln were 5, 1 and 3 in the prefrontal cortex and 5, 5 and 2 in the striatum, proving the reliability of the quantification of the metabolites of the glutamatergic and GABAergic neurotransmission systems. The high spectral quality achieved over the entire chemical shift range (0.5–4.2 ppm) ensured reliable and reproducible quantification of each of the brain metabolites. Significant differences in myo-inositol (Ins) and taurine (Tau) between WKY and SHR rats were found for both regions. In addition to aforementioned metabolites, strain-differences in glutamine (Gln) and glutathione (GSH) level in prefrontal cortex and phosphocholine (PCh) and in total choline level in striatum were observed. Strain dependent changes of metabolites from two brain regions are shown in Fig. 2. In spite of the fact that scyllo-Ins and N-acetylaspartylglutamate (NAAG) signal were incorporated into the basis set of LCModel as a model component corresponding concentration was only possible to quantify in the striatum. This data of absolute metabolite concentration will serve as a reference for future MRS studies investigating the psychotherapeutic effect of neuroleptics on juvenile rat brain.Optimized STEAM sequences in combination with advanced single-shot frequency and phase correction, and image-based shimming enables the quantification of brain metabolites with high spectral fidelity and reproducibility allowing for the assessment of even tiny differences between the metabolic profile of WYK and SHR rats.