Histochemical Differentiation of Motor Neurones and Interneurones in the Anterior Horn of the Cat Spinal Cord

Abstract

THE neurones of the anterior horn are a heterogeneous population of physiologically different cells. Alpha and gamma motor neurones, Renshaw cells and interneurones are recognized components¹. Alpha motor neurones have been divided further into F and S types according to the fast and slow contractile properties of the muscle fibres that they innervate². Anatomic investigations, largely by retrograde chromatolysis, have shown that the different neurones are intermingled, and that the larger are mainly alpha motor neurones while the smaller are a heterologous group of gamma motor neurones, Renshaw cells and interneurones^3,4. Staining techniques selective for the Golgi body differentiate motor neurones from interneurones by the direction of their axons, but standard histological methods result in uniform staining without significant morphological distinction. We have used histochemical staining reactions to attempt neuronal differentiation in the anterior horn.