THE AFFERENT PROJECTIONS OF THE LOCUS COERULEUS IN THE RAT AN HRP STUDY / 解剖学报

ABSTRACT

The afferent projections of the locus coeruleus (LC) were studied in 32 rats following the microelectrophoretic delivery of HRP into the different parts of the LC. It was revealed that the LC received afferent fibers widely from the brain, and some topographic localization may exist. Following the injection of HRP into the rostral part of the LC, HRP labeled neurons were observed widely distributed in the brain and spinal cord. In the telencephalon, moderately HRP labeled neurons were observed in the bed nucleus of the stria terminalis, medial and lateral preoptic area, and a few HRP labeled neurons were observed in the areas 13 and 14 of the insular cortex, areas 8 and 10 of the frontal cortex and the central amygdaloid nucleus. In the diencephalon, numerous labeled neurons were observed in the lateral and dorsal hypothalamic area, and a few labeled neurons were observed in the paraventricular nucleus, ventromedial nucleus and arcuate nucleus of the hypothalamus, the parafascicular nucleus of the thalamus, zona incerta and the lateral habenular nucleus. In the brain stem, cerebellum and spinal cord, numerous labeled neurons were observed in the periventricular gray substances, reticular formation and Vestibular nuclei, and a few labeled neurons were observed in the lateral reticular nucleus, solitary nucleus, prepositus nucleus, nucleus of the Spinal tract of the trigeminal nerve, nucleus raphe magnus, nucleus raphe pontis, nucleus raphe dorsalis, parabrachial nucleus, substantia nigra, nucleus lemnisci lateralis, fastigial nucleus, and spinal cord. However, following the injection of HRP into the caudal part of the LC, labeled neurons were observed only in the brain stem, cerebellum and spinal cord, no HRP labeled neurons were found in the telencephalon and diencephalon.