Abstract
A histopathological study has been performed on the peripheral nervous tissue of pigeons fed on polished rice and rats in experimental deficiencies of thiamine, riboflavin and niacin. In peripheral nervous tissue of pigeons fed on polished rice, marked degenerative changes of neuron somas, nervous fiber and end-plates were observed. In case of thiamine deficiency, lesion was initiated by an appearance of myelin droplets of Schmidt-Lantermann's incissures and dissociation of myelin sheath from axolemma. The changes were followed by disintegration of myelin sheath, later causing bubbling and destruction of axons, more marked in distal portion of nerve fibers. Axonal reaction were found in both motor cells of spinal cord and sensory spinal ganglion cells. These changes were identical to those of experimenfal pyruvic acid administration. However lowering of choline esterase activity and disruption of end-plates of motor neurons were obsserved in thiamine deficiency, whereas the changes were not found in pyruvic acid application. Riboflavin deficiency was characterized by shrinkage and clumping of neurofibrils, and acute swelling or liquefaction of nerve cells in spinal cord, spinal ganglia and Auerbach's and Meissner's plexus. In spite of severe damages in neuron somas, alterations of distal nerve fibers were surprisingly slight, possibly due to rapid course to death of animals. In niacin deficiency, both nerve cells and fibers were damaged at the same time. Degenerative changes were demonstrable in motor, sensory and vegetative neurons. Lowering of choline esterase activity and destruction of end-plates were also demonstrated.
