Wright L L
Department of Anatomy, Boston University School of Medicine, Massachusetts 02115.
J Comp Neurol. 1987 Sep 8;263(2):259-64. doi: 10.1002/cne.902630208.
The number of superior cervical ganglion (SCG) neurons does not differ for males and females on the day of birth, but by 15 days, after most of the normal neuron death has occurred, males have significantly more neurons than females. This difference persists in the adult. The present study was undertaken to determine whether the presence of afferent input to the SCG is required for the development of this sex difference. Bilateral transection of the cervical sympathetic trunk, which deafferents the SCG neurons, or a sham operation was performed on male and female Sprague Dawley rats on the day of birth. Numbers of neurons were counted in SCGs of animals sacrificed on either postnatal day 4 or 15, before or after normal development of the SCG sex difference. At 4 days, the number of SCG neurons in sham-operated males and females were not different, but by 15 days, females had lost a significant number of neurons, whereas the males had not. Transection of the cervical sympathetic trunk led to a significant loss of over 6,000 SCG neurons by postnatal day 4 in both males and females. Whereas some of this loss is due to axotomy of caudally projecting SCG neurons, at least half of the neuron loss is due to removal of the afferent input. At 15 days, sham-operated males had significantly more SCG neurons than did sham-operated females, but the gender difference was not significant in animals with neonatally deafferented ganglia. Thus, the normal development of the gender difference in SCG neuron numbers requires an intact afferent input.
出生当天，雄性和雌性大鼠的颈上神经节（SCG）神经元数量并无差异，但到15天时，在大多数正常神经元死亡发生之后，雄性大鼠的神经元数量显著多于雌性。这种差异在成年期依然存在。本研究旨在确定SCG性别差异的形成是否需要传入神经输入。在出生当天，对雄性和雌性斯普拉格-道利大鼠进行双侧颈交感干横断术（使SCG神经元失去传入神经）或假手术。在出生后第4天或第15天，即在SCG性别差异正常发育之前或之后，对处死的动物的SCG进行神经元计数。在4天时，假手术的雄性和雌性大鼠的SCG神经元数量并无差异，但到15天时，雌性大鼠的神经元数量显著减少，而雄性大鼠则没有。颈交感干横断术导致出生后第4天雄性和雌性大鼠的SCG神经元均显著减少超过6000个。虽然这种减少部分是由于SCG神经元向尾侧投射的轴突切断，但至少一半的神经元减少是由于传入神经输入的去除。在15天时，假手术的雄性大鼠的SCG神经元数量显著多于假手术的雌性大鼠，但在新生期神经节去传入神经的动物中，性别差异并不显著。因此，SCG神经元数量性别差异的正常发育需要完整的传入神经输入。
