A simple method for isolation of the anteroventral periventricular and arcuate nuclei of the rat hypothalamus

Objectives: The aim of the present study was to establish a simple and reliable method for separation of anteroventral periventricular (AVPV) and arcuate (Arc) nuclei in the rat hypothalamus to evaluate expression of peptide mRNAs in these nuclei using RT-PCR. Methods: Two female Sprague -Dawley rats were perfused transcardially with 10% buffered formalin. Brains were immediately removed and diencephalon was dissected out by two coronal sections. The first section was made at rostral of optic chiasm and the second section at the caudal end of mammillary bodies. To separate the AVPV and Arc nuclei, the third section was made rostral of infundibulum which placed one part of the optic tract in rostral (anterior) division and its other part in the caudal (posterior) division. The rostral and caudal divisions were separately post-fixed and cut coronally and serially using a cryostat at 30-μm thickness. Sections from rostral and caudal divisions of the diencephalon were stained with cresyl violet. Landmarks for Arc and AVPV nuclei were evaluated in each section. Results: Arc and AVPV nuclei were not simultaneously detected in any stained section in rostral or caudal divisions of diencephalon. Conclusion: By the presented method, it is easily possible to separate AVPV and Arc nuclei to evaluate the expression pattern of mRNA of peptides expressed in these two hypothalamic nuclei of the rat by using RT-PCR or other molecular methods.