Quantitative Autoradiography as a Tool to Study Receptors in Neural Tissue. Studies on 3H-Ouabain Binding Sites and Correlation with Synaptic Protein Phosphorylation in Different Brain Areas

Abstract

During recent years quantitative receptor autoradiography has been extensively used in studies on the distribution of transmitter receptors in the central nervous system (see Unnerstall et al. 1981, 1982; Palacios et al. 1981; Penney et al. 1981; Rainbow et al. 1982; Fuxe et al. 1983). Quantitative studies have been performed both by counting silver grains on nuclear emulsion and by computerized densitometry with tritium sensitive film (Unnerstall et al. 1981, Palacios et al. 1981). Saturation analysis can also be performed by quantitative receptor autoradiography as first shown hy Penney et al. (1981), who determined the Kd and B values for 3H-muscimol binding sites in brain sections using 14Cmax-plastic standards, which had been calibrated to tritium. The problem in quantitative receptor autoradiography has been to obtain suitable standards in view of the quenching, taking place in brain tissue and which is different in white matter and grey matter due to differences in self absorption (Alexander et al. 1981; Geary and Wooten, 1983). Previously, both tritium containing tissue paste standards and tritium containing plastic standards have been used. The 3H-plastic standards have been calibrated by coexposing plastic squares, containing a range of tritium concentrations, and hemi- sections from tritium containing brains. The tissue radioactivity in the contralateral half was then determined in various regions by scintillation spectroscopy.