Huntington's disease / edited by Thomas N. Chase, Nancy S. Wexler, André Barbeau.
- Date:
- 1979
Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Credit: Huntington's disease / edited by Thomas N. Chase, Nancy S. Wexler, André Barbeau. Source: Wellcome Collection.
752/856 page 720
![720 NEUROTRANSMITTER RECEPTOR ALTERATIONS IN HD ['н] SPIROPERIDOL (рМ) FIG. 2. Saturation curve and Scatchard plot of зн-spiroperidol bound to a nornnal (open circle) and a HD (open square) frontal cortex. Saturation curve of specific ^H-spiroperidol bound at receptor concentrations of 4.5 рм for control and 4.7 рм for HD tissue. Inset: Modified Scatchard plot of saturation isotherms. The apparent Kd values (from the slope of the line) are 70 рм for both normal and HD tissue. Maximum specific binding (from the y-intercept) was 64 fmoles/ mg protein for normal and 44 fmoles/mg protein for HD frontal cortex. These experiments were replicated two to three times. (From Reisine et al., réf. 25, with permission). sites in choreic brains. Both of these studies revealed no aherations in the density of GABA receptors in other choreic brain regions studied. Recently, Toffano et al. (36) have suggested the existence of an endogenous inhibitor of ^H-GABA binding in rat brain homogenates. This study reports that the inhibitor can be removed from brain homogenates after pretreatment with the nonionic detergent Triton X-100 and extensive washing. Since in previ¬ ous studies of GABA receptor binding in HD (9,17) the tissues were not treated with Triton X-100, measurement of GABA receptors in these studies may have been obscured by the presence of variable amounts of an inhibitor of 'H-GABA binding. TABLE 2. ^H-Muscimo! binding in control and HD brain (fmoles/mg protein) Brain homogenates were incubated for 30 min at 37°C with 0.05% Triton X-100, then washed three times by centrifuging and resuspending in fresh buffer, prior to assay. ®H-Muscimol binding was determined at a concentration of 20 пм. Binding in the presence of 0.1 тм GABA was defined as nonspecific binding and was subtracted from total binding to obtain specific ^Н- muscimol binding. Binding was determined as previously described (2).](https://iiif.wellcomecollection.org/image/b18021888_0753.JP2/full/800%2C/0/default.jpg)
