Mini-review: multiple developmental forms of parkinsonism. The basis for further research as to the pathogenesis of parkinsonism.

A range of extrapyramidal disturbances have been reported in children following early brain damage. In adults, damage to the basal ganglia can elicit abnormal motor activity in either direction; it would seem reasonable that the same would apply to damage occurring at an earlier developmental stage. The Viennese paediatrician Widhalm described a hypokinetic/parkinsonoid syndrome ("infantile hypokinetic-hypertonic syndrome with Parkinson symptomatic") presented by a significant minority of the children with extrapyramidal movement disturbances, corresponding to the mild rigid-akinetic type of Parkinson's disease. In contrast to classical parkinsonism, but consistent with some forms of post-encephalitic parkinsonism, the syndrome was reversible, although only after L-DOPA therapy. Widhalm's observation that at least one form of childhood parkinsonism can be cured with L-DOPA also suggests that the amino acid plays a more active role than mere replacement therapy in children, perhaps also acting as a neurotrophic agent. It is proposed that environmental factors, including viral and risk factors associated with pregnancy and birth, together with genetically determined lability, may increase the incidence of early hypokinesia/parkinsonism in particular and of Parkinson's disease in later life by disturbing the immature basal ganglia at critical developmental stages. The spectrum disorder of Parkinson's disease thereby occurs as a number of various etiopathologically distinct syndrome subtypes, including early onset developmental forms caused by in utero or early post partum trauma.

[Effect of manganese on the brain extrapyramidal development of rat offspring].

The effect of manganese (Mn) exposure on the behavior and extrapyramidal system of offspring were studied. Pregnant rats and their offspring in the experimental group were exposed to manganese from drinking water containing 2 g/L (low Mn-exposed group) or 10 g/L (high Mn-exposed group) of MnCl2 respectively. The latent period for running from the center field to any arm of Elevated Plus Arm Maze of both low and high Mn-exposed group was significantly reduced. But the latent period for reaching the platform above the water in Morris Water Maze of the Mn-exposed group was not different from that of control group. There was a significant increase in the areas, glial fibrillary acid protein(GFAP) immunoreactivity and the average proportional densities of GFAP-positive elements in nucleus caudate and accumbens in the high Mn-exposed group, and a significant reduction in the tyrosine hydroxylase immunoreactivity (TH) and average proportional densities of TH-positive elements in substantia nigra, ventral tegmentum area of midbrain and nucleus caudate in the high Mn-exposed group.

The adult organization and development of the rubrospinal tract. An experimental study using the orthograde transport of WGA-HRP in the North-American opossum.

We have employed the orthograde transport of wheat germ agglutinin conjugated to horseradish peroxidase to study the organization of rubrospinal connections in adult and pouch young opossums. Our results suggest that: in the adult opossum rubrospinal axons are distributed more widely than suggested by previous studies; rubrospinal projections are formed postnatally in the opossum, but much earlier than corticospinal connections; rubrospinal axons do not grow synchronously, as a massive bundle following a few leading axons, but by addition of axons over a protracted period of time; and the growth of rubral axons into the spinal gray matter follows a predictable rostral to caudal gradient as well as a proximal to distal one relative to the tract. Rubrospinal development is discussed in light of the growth of cerebellar and cortical axons into the red nucleus and the development of motor function.