Coupled intracellular horseradish peroxidase-monoamine oxidase histochemistry: description of the technique and its application to the study of physiologically identified tuberomammillary neurons.

A technique is described which couples visualization of intracellular horseradish peroxidase (HRP) with histochemical localization of monoamine oxidase (MAO), permitting simultaneous study of histochemistry, morphology and physiology in a single neuron. Using this technique, individual neurons int he tuberomammillary nucleus of the hypothalamus were stained in a Golgi-like fashion, revealing their somatodendritic morphology in detail. The technique has general applications as a method for conferring cytochemical specificity to intracellular staining of other MAO positive neurons, to retrograde transport of HRP by MAO positive neurons, as well as for ultrastructural studies of positively stained neuronal elements.