ULTRA-CYTOCHEMICAL LOCALIZATION OF THIAMINE MONOPHOSPHATASE ACTIVITY IN THE SUBSTANTIA GELATINOSA OF THE RAT SPINAL-CORD

Thiamine monophosphatase activity in the substantia gelatinosa of rat spinal cord was studied under the electron microscope. The reaction products were chiefly localized on the plasma membrane of electron dense sinusoid axon terminals. The precipitates were occasionally localized on the plasma membrane of neighboring axons and dendrites. However, no thiamine monophosphatase activity was found in membrane-bound dense bodies, the Golgi apparatus, the associated so-called GERL system, and the endoplasmic reticulum of the substantia gelatinosa nerve cells. It is postulated that acid phosphatase activity on the plasma membrane of electron dense sinusoid axon terminals in the substantia gelatinosa may have some function related to thiamine metabolism. © 1979, JAPAN SOCIETY OF HISTOCHEMISTRY AND CYTOCHEMISTRY. All rights reserved.