INVESTIGATION OF THE ROSTRAL PROJECTIONS FROM THE RAPHE NUCLEI USING THE RETROGRADE TRACER CHOLERA TOXIN
Stem Cell Unit, Anatomy Department, College of Medicineand King Khalid University Hospital,King Saud University.
The aim of this study was to investigate the localization of possible serotonergic (5-HT) projections from the dorsal and median raphe nuclei within the neostriatum of AS and AS/AGU rats a PKC-C mutant which shows movement disorders and amine depletions in the caudate –putamen.In order to determine the connectivity between the raphe and the caudate-putamen, the retrograde tracer cholera toxin b (CTb) was injected into dorsal caudate-putamen (DCPU). ICC was carried out for CTb and 5-HT within the midbrain and cell counts were carried out.The results suggest that half the serotonergic cells in the dorsal raphe project to the DCPU, however no cells in the median raphe do so. Moreover, serotonergic cells in the dorsal raphe of AS/AGU mutants are substantially depleted compared to the AS parent strain. The data suggest a further dysfunctional link between the DCPU and one of its aminergic inputs which could underlie the motor deficits seen in this mutant