含Calbindin－D28K mRNA神经元在大鼠脊髓中的分布──原位杂交组织化学法观察

用原位杂交组织化学技术，对大鼠脊髓内含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ＫｍＲＮＡ的神经元的分布状况进行了观察。发现含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ＫｍＲＮＡ的神经元见于脊髓灰质的各层，但是，不同区域或核团中所含阳性神经元的数量和标记强度各不相同。其中含强阳性神经元的部位有：Ⅰ、Ⅱ、Ⅳ、Ⅴ层及前角外侧运动柱的内侧部；含中等阳性神经元的部位有：Ⅲ、Ⅷ层及中间带；有的区域仅含弱阳性神经元，如：Ⅵ层及中央区，而中间带外侧核及前角的大型运动神经元未见到阳性杂交信号。Ｃａｌｂｉｎｄｉｎ－Ｄ２８ＫｍＲＮＡ在大鼠脊髓内的区域特异性分布特点，提示其在神经系统的某些生理功能中可能有重要作用。

LOCALIZATION OF NEURONS CONTAINING CALBINDIN-D28K mRNA IN THE RAT SPINAL CORD── AN IN SITU HYBRIDIZATION ANALYSIS

Calbindin-D28K (CaB)is a kind of vitamin D-dependent calcium-binditig proteins(CaBP) and its distributions in the nervous system lave been demonstrated immunohistorhemically. However,the problem of spercificity of the CaB antiserum, which is also generally used to combine with other CaBP because of the occurance of homology in their sequences,makes the interpretation of these immunhistochemical results rather difficult. So we investigated the localization of CaB mRNA in rat spinal cord by in situ hybridization histochemistry with a specific oligonucleotide. Adult Sprague-Dawley rats were killed by decapitation under sodium penbarbital anesthesia. The spinal cord was quickly removed and frozen in powdered dry ice. Sections were cut on a cryostat at 10 ～15μm thickness and thaw-mounted on gelatin-coated slides. Hybridization was performed by incubating these sections with the probes labeled with [α-￣(35)S]dATP at 3’end. Then the sections were washed at high stringency and examined by emulsion autoradiography. The result showed that the labeled neurons were revealed in all layers of the spinal cord, but they were distributed unevenly. The highest ainount of CaB mRNA were found in lamina Ⅰ、Ⅱ of all the.segments. Some other regions such as lamina Ⅳ,Ⅴ and the medial part to the lateral moter column in the ventral horn also contained neurons labeletl strongly. The regions containing moderately to weakly labeled neurons were as follows:lamina Ⅲ、Ⅷ、Ⅵ and the central gray region. Whereas. the dorsal nucleus of Clarke,the intermediolateral nucleus and the large motoneurons were devoid of positive signals. Therefore,the neurons containing CaB mRNA showed a region-specific distribution in rat spinal cord, suggesting an important role of CaB in nervous system.