ABSTRACT
After severance the ventral spinal roots in 10 dogs, the distribution of the anterograde degeneration was studied by means of Nauta's technique with the following conclusions:1. After sectioning the ventral roots, degenerating fibers (including preterminal and terminal fibers) appeared regularly in the spinal cord and medulla oblongata. This confirms that there are afferent fibers which project into the central nervous system via the ventral spinal roots.2. These degenerating fibers ascended not only in the posterior funiculi, but also in the gray matter, so that the preterminal and terminal degenerations of the terminal branches or collateral branches were found in the columna grisea posterior of the thoracic and cervical segments above the surgically operated segments of the spinal cord.3. The preterminal and terminal degenerations were found in the reticular areas of the nucleus gracilis of the medulla oblongata and around the non-cluster cells.4. Degenerating fibers were unequally distributed, most of them located ipsilaterally. The degenerating fibers decreased in number in rostral segments.5. Afferent fibers in ventral roots differ from those in dorsal roots in distribution:a) From the operated segment and to far more rostral segments, afferent fibers of the ventral root were distributed in a more medial position in the spinal dorsal gray column, viz, "medial tendency", and then ascended after interposing into the funiculi gracilis. This is different from the afferent fibers of the dorsal root in the control group which were distributed in "equal tendency" in the dorsal column and took a "lateral addition fashion" of entering the funiculi gracilis.b) Apparently, much more afferent fibers in ventral roots projected contralaterally than those in the dorsal roots.c) It was also characteristic that the afferent fibers in ventral roots projected further toward the rostral segments of the spinal cord.
ABSTRACT
Huntington disease (HD) rat model was produced by injection of ibotenic acid (IA) into the head of right caudate putamen (CP). One month post lesion, fetal (El5-17) striatal cell suspension was implanted into the lateral ventricle ipsilateral to the lesion, and the rats were devided into four groups; group I normal control rats (n=8), group II model control rats (n=10), group III simple transplanted with fetal striatal cell suspension, (n=10, ST group), group IV grafted with striatal cell suspension containing laminin (n=6, LST group). Three and six months after grafting, active avoidence test was carried, the results showed that there were significant differences bewteen grafted groups and model control group at three and six months, and no significant differences between LST group and normal group either in three or six months whereas between ST group and normal group no significant difference only can be found at six months. Overnight locomotor activity was measured in each group at six months post grafting, the results indicated that the locomotor behaviour of model control group was hyperactive whereas the overnight hyperactivity was compensated completely in the grafted groups. After the behavioural test, the rat brain was investigated morphologically. The head of the lesioned CP was atrophied and the graft was located at the dorsal part of the atrophied CP and projected into the lateral ventricle. The volume of the graft area of LST group was larger than that of ST group. ChAT, GABA and Leu-ENK positive neurons were found in the graft area of the two grafted groups and their shape and size were similar to those of nomal CP. The processes of AChE positive neurons in the graft of LST group were more and longer than that in the graft of ST group. The results indicated that the fetal striatal neurons implanted into the lateral ventricle of HD model rats not only can survive and grow well but also ameliorate the behavioural deficits of the IA lesioned rats and the laminin may supports the neuronal suvival and growth in vivo.