Zoological Studies

Distribution of Precerebellar Cholecystokininergic Neurons in the Perihypoglossal Nuclei of the Gerbil

Shih-Hsiung Lee, Chi-Yu Tseng, Chen-Yuan Wen and Jeng-Yung Shieh (2002) This study aimed to examine the distribution of vermis-projecting cholecystokinin-immunoreactive (CCK-ir) neurons in perihypoglossal (PH) nuclei of the gerbil. Revealed by immunohistochemistry, CCK-ir neurons were mainly distributed in the nucleus of Roller (Ro) and prepositus hypoglossal nucleus (Pr), with fewer cells being located in the nucleus intercalatus (Ic). Small CCK-ir cells made up the majority of cells in the Ro, Ic, and Pr, the remainder being medium-sized. Following multiple injections of horseradish peroxidase (HRP) into the vermal cortex, the majority of CCK-positive neurons in the Ro, Ic, and Pr were labelled. On closer analysis, about 90% of CCK-ir cells in PH nuclei were double labelled. Since the predominant cells in the subnuclei of the PH are CCK-ir, and the subnuclei Ro and Pr are known to give rise to CCK-ir mossy fibers in the vermis of the cerebellum, we conclude that CCK may serve as a putative neurotransmitter or neuromodulator in this projection.