Journal of Neuroscience, Vol 6, 2604-2610, Copyright © 1986 by Society for Neuroscience
A structure-activity study on the sucrose taste antagonist methyl 4,6- dichloro-4,6-dideoxy-alpha-D-galactopyranoside
V Vlahopoulos and W Jakinovich Jr
In order to assess the effect of the antagonist methyl 4,6-dichloro-4,6-
dideoxy-alpha-D-galactopyranoside (MAD-diCl-Gal) upon the gerbil's chorda
tympani sucrose taste response, we tested several concentrations of this
compound, as well as single concentrations of closely related derivatives,
and found that MAD-diCl-Gal was the most potent inhibitor tested. It
appears that the inhibition mechanism is very specific. For example, we
have found that 2 chlorine atoms at the C-4 and C-6 positions on the
glucopyranoside ring are required for inhibition. In addition, with regard
to the orientation of the chlorine atoms, the galacto derivative seems to
be more potent than the gluco derivative. We have also found that the
methyl glycoside is more potent than the free sugar. With regard to the
orientation of the methyl group, MAD- diCl-Gal is more potent than its
beta-anomer. (Because of this discovery of the methyl group enhancement and
orientation effect, we shall discontinue using the acronym diCl-Gal and
replace it with the more specific MAD-diCl-Gal.) Of particular significance
is the fact that there appears to be a structure-activity relationship
between the most active stimulants and inhibitors in that the requirement
for an axial orientation at C-1 and the enhancement by the methyl group at
that position are the same in both cases. These results suggest that both
the stimulator and the antagonist are acting at the same receptor
site.(ABSTRACT TRUNCATED AT 250 WORDS)