ABSTRACT
The divergent axon collaterals from neurons in locus coeruleus have been in vestigated by means of fluorescent double labeling technique in 36 rats.Different fluorescent tracers, Fast Blue, Nuclear Yellow, Propidium iodide, Bisbenzimide, Evans Blue, DAPI and Primuline were injected into the prefrontal cortex, the thalamus, the hippocampus, the cerebellum and cervical cord to observe the double retrograde labeling neurons of the locus coeruleus.Following unilateral or bilateral combined injections of two fluorescent tracers into the thalamus and cerebellum, the hippocampus and cerebellum, the hippocampus and thalamus, the larefrontal cortex and cerebellum, the prefrontal cortex and thalamus, the prefrontal cortex and cervical cord, the hippocampus and cervical cord, the cerebellum and cervical cord, double labeled cells were found in locus coeruleus, and some topographical organizations were also found.
ABSTRACT
Divergent axon collaterals from forebrain and brainstem to the dorsal hippocampus in the rat were examined by means of HRP method and fluorescent retrograde double labeling method.HRP solution was injected into the left or right dorsal htppocampus of 3 rats. HRP labeled cells were observed in the bilateral medial parts of medial septal areas, vertical limbs of the diagonal band of Broca, supramammillary nuclei, submammillothalamic nuclei, superior central nucleus and locus ceruleus.PI and Bb solution were injected into the left and right hippocampus of 3 rats separately. Many retrograde double labeled cells were found in the nuclei mentioned above.The results indicate that the retrograde double labeled ceils in these nuclei may divergently projected to both the left and right dorsal hippocampi. They play an important role in harmonizing the activity of bilateral hippocampi.
ABSTRACT
Skin-visceral divergent projections of cholecystokinin(CCK)-containing dorsal root ganglion neurons were studied by combined technique of fluorescent double-labelling and immunohistochemistry. Fast Blue(FB) and Nuclear Yellow (NY) were injected into the coeliac ganglion and the cutaneous branches of left 9th-11th intercostal nerves, respectively. Three kinds of neurons labelled with fluorescein were observed in T_(9-11) dorsal root ganglia under Nikon fluorescence microscope with 365 nm excitation light: FB-labelled neurons with blue-fluorescing cytoplasm; NY-labelled neurons with yellow-fluorescing nucleus and double-labelled neurons with blue cytoplasm and yellow nucleus. The double-labelled neurons were found to be 2.8％ of total labelled neurons.The sections containing fluorescein labelled neurons were then stained by CCKimmunohistochemical procedure. Four kinds of neurons could be identified: NY-neurons, with CCK-immunoreactivity (NY+CCK); FB-neurons with CCK-immunoreactivity(FB + CCK);NY + FB neurons with CCK-immunoreactivity(NY + FB + CCK); Single CCK-positive neurons. NY + FB + CCK triple-labelled neurons accounted for approximately 11.5％ of NY + FB double-labelled neurons,and 0.4％ of all CCK-positive neurons.The findings clearly indicated that the peripheral processes of some sensory dorsal root ganglion neurons project divergently to both skin and visceral structure, and contain CCK. The present results suggest that the peripheral dichotomization of the dorsal root ganglion nearons might converge sensory inputs from both skin and visceral fields, and thus not only provide one of the structural basis for the referred pain but also reveal that CCK might play a mediation role in the skin-visceral reflection and referred pain.