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Comparison between brain paste and polymer [125I]standards for quantitative receptor autoradiography
1Parke-Davis Research Unit, Addenbrooke's Hospital Site, Cambridge, U.K.
Journal of Neuroscience Methods
|August 1, 1988
Summary
Polymer standards for quantitative receptor autoradiography closely mimic rat brain tissue standards at lower radioactivity levels. This finding validates their use in accurate receptor density measurements.
Area of Science:
- Neuroscience
- Biochemistry
- Radiochemistry
Background:
- Quantitative receptor autoradiography relies on accurate calibration standards.
- Tissue-based standards are traditional but can be variable.
- Polymer-based standards offer a potential alternative for consistency.
Purpose of the Study:
- To compare the performance of [125I]-labeled rat brain tissue standards with commercial polymer-based standards.
- To evaluate the suitability of polymer standards for quantitative receptor autoradiography.
Main Methods:
- Preparation of [125I]-labeled grey and white matter rat brain tissue standards.
- Comparison with commercially available polymer-based standards across various radioactivity levels.
- Exposure of standards to two radiation-sensitive films (Hyperfilm [3H] and betamax) for 1-14 days.
- Analysis of the relationship between optical density and radioactivity using linear and quadratic models.
- Assessment of the impact of section thickness (5-20 microns) on linearity.
Main Results:
- A linear relationship was observed between the natural log of optical density and radioactivity for tissue standards across exposure times.
- No significant differences were found between the slopes and intercepts of tissue standards and the lower activity levels of polymer standards.
- The linear relationship was lost at higher radioactivity levels of polymer standards, with a quadratic model providing a better fit.
- A linear relationship was confirmed between section thickness and optical density within the typical range used in receptor studies.
Conclusions:
- Lower activity levels of polymer-based standards are comparable to rat brain tissue standards for quantitative receptor autoradiography.
- Polymer standards can be reliably used for accurate receptor density measurements in autoradiography.
- The findings support the use of polymer standards as a viable alternative to tissue standards, enhancing reproducibility in receptor studies.