Predominance of supraspinal innervation of the left ovary.

In our previous studies using the viral transneuronal tracing technique we demonstrated the spinal and supraspinal components of the ovarian innervation. Since increasing number of data indicate the presence of morphological and functional laterality in the control of gonadal functions, we aimed to investigate whether cerebral structures trans-synaptically involved in the innervation of the ovary exhibit asymmetry or not. In one of the studies the left or the right ovary was injected with the red fluorescent protein expressing pseudorabies virus and the number of infected "red" autofluorescent neurons from the right and the left ovary was compared. In another study in order to have distinct labeling of cell groups connected with the right- and left-sided ovary in the same animal, a dual viral labeling was applied. The left- and right-sided ovary were inoculated with genetically engineered pseudorabies virus expressing a red fluorescent protein or a green fluorescent protein gene. Viral infection of brain nuclei including the dorsal vagal nucleus, caudal raphe nuclei, A5 noradrenergic cell group, hypothalamic paraventricular nucleus, from the left ovary in each case was enhanced when compared with labeling from the right gonad. Data suggest a predominance in the supraspinal innervation of the left ovary.