Giannessi F
Istituto di Anatomia Umana Normale, Facoltà di Medicina e Chirurgia, Università di Pisa, Italy.
Anat Embryol (Berl). 1989;180(2):175-8. doi: 10.1007/BF00309769.
The innervation pattern of the paratympanic organ was studied by TEM. The paraympanic organ is a small tapering vesicle, typical of birds, situated in the medial wall of the tympanic cavity; it contains hair cells which are similar to type II receptors of the acoustic-lateral system; these cells are characterised by synapses which are not only afferent and efferent, as previously described, but also reciprocal with efferent fibers. Our observation revealed some efferent nerve fibers which form a relationship with hair cells containing synaptic bodies situated next to the plasma membrane and near the fibers themselves. Since synaptic bodies are commonly considered to be the site where the transmission of the impulse from the receptor to the nerve fiber takes place, our pictures suggest that the efferent fibers and hair cells may be either presynaptic or postsynaptic with respect to each other in the paratympanic organ. The hypothesis is formulated that reciprocal synapses allow interaction between hair cells, thus determining an increase in the contrast of information sent by the paratympanic organ to the CNS.
通过透射电子显微镜（TEM）研究了鼓室旁器官的神经支配模式。鼓室旁器官是一种呈锥形的小囊泡，为鸟类所特有，位于鼓室的内侧壁；它含有毛细胞，类似于听觉-侧线系统的II型感受器；这些细胞的特征在于其突触不仅如先前所述有传入和传出突触，而且与传出纤维形成交互突触。我们的观察发现一些传出神经纤维与含有突触小体的毛细胞形成联系，这些突触小体位于质膜旁边且靠近纤维本身。由于突触小体通常被认为是冲动从感受器传递到神经纤维的部位，我们的图片表明在鼓室旁器官中传出纤维和毛细胞可能彼此互为突触前或突触后。由此提出假说：交互突触允许毛细胞之间相互作用，从而增加鼓室旁器官向中枢神经系统发送的信息对比度。
