Many experiments have been undertaken in order to study the role of the central nervous system for the regulation of the white blood cell in peripheral blood, and many authors asserted that the diencephalon, especially the hypothalamus participates in the regulation of leukopoiesis in several animals.
However, very little is known as to the exact regions of the central nervous system engaged in the contral of the number of white blood cells in peripheral blood.
This author experimentally observed the changes of the number of white blood cells in peripheral blood by the stimulation of several parts of the central nervous system with the injection of typhoid vaccine by using the stereotaxic apparatus.
Korean white male rabbits weighing 1.8kg were used as experimental animals and 0.05cc of 10:1 typhoid vaccine was injected in the both regions of central nervous system symmetrically.
The followings were observed:
1. A rapid and significant reduction in the number of white blood cells in pheripheral blood was observed in rabbits by stimulation with the injection of typhoid vaccine into the anterior hypothalamus and median eminence like in the case of intravenous injection of typhoid vaccine.
2. The degree of reduction in the number of white blood cells was greater in the cases of injection into the anterior hypothanlamus and intravenously than into the median eminence.
The time at which the maximum reduction of the white blood cells occured was earlier in the cases of injection into the anterior hypothanlamus and the median eminence than given intravenously.
3. The reduction in the number of white blood cells in pheripheral blood which occured by injection of typhoid vaccine seemed to be due to the reduction of the segmented nuclear leukocytes.
4. Irregular and unsignificant changes in number of white blood cells were also observed in rabbits by the injection of typhoid vaccine into the preoptic area, posterior hypothalamus, mammillary body, midhypothalamus, hippocampus, midbrain and amygdala.
The above mentioned experimental findings lead this author to conclude that the regulation center which cases the reduction in the number of white blood cells in peripheral blood exists in the anterior hypothalamus and the median eminence respectively.
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