[Light-microscopic studies of locus coeruleus region of the mouse]

In an attempt to give some contribution to the morphology of locus coeruleus (LC) in the ddY mouse (weighing about 20 g), we made light-microscopic investigations using several staining methods in normal condition. First, we studied the cytoarchitectonics and cell numbers of LC by the Klüver-Barrera method and amine demonstrating wet fluorescent method. LC of the mouse measured 600 +/- 60 micrometers in antero-posterior extent in the dorso-lateral tegmental area. At the rostral part of LC small number of constituent cells were disseminated, the middle part (principal part) showing the triangle-shaped cell accumulation with an apex directing to the IV ventricle. The caudal part forming small accumulation of cells ended directly beneath the IV ventricle. Number of unilateral LC cells amounted to 1250 +/- 92 by Klüver-Barrera method, while 1326 +/- 44 by the wet fluorescent method. The LC was cytoarchitectonically divided into the dorsal and ventral parts. The cell size of the dorsal part averaged (16.2 +/- 2.8) x (25.5 +/- 4.6) micrometers along the longest and shortest axes, while that of ventral part (17.3 +/- 3.1) x (30.2 +/- 5.6) micrometers.