Table 2

[³H]R214127 is specific for the mGlu1 receptor relative to the mGlu2, -3, -4, -5 or -6 receptor

SB	mGlu1	Wild-Type	mGlu2	mGlu3	mGlu4	mGlu5	mGlu6
	fmol/mg of protein
R193845 as blank	6057 ± 1456	65	0	0	82	38	0
Various blanks	N.D.	N.D.	34^2-a	0^2-a	57^2-b	0^2-c	0^2-a

The specific binding of 20 nM [³H]R214127 to 40 μg of membranes from wild-type (CHO-dhfr⁻) cells or from CHO-dhfr⁻ cells expressing rat mGlu2, -3, -4, -5, or -6 receptors is compared with binding of 10 nM [³H]R214127 to 20 μg of rat mGlu1a receptor CHO-dhfr⁻ membranes. Various compounds were used to define nonspecific binding. Specific binding (SB) data from rat mGlu1a receptor CHO-dhfr⁻membranes are the mean ± S.D. of three experiments performed in duplicate. Other SB data are the mean of duplicate determinations from one experiment.

N.D., not determined.
↵2-a 1 mM glutamate was used to determine non-specific binding.
↵2-b 0.1 mMl-serine-O-phosphate was used to determine nonspecific binding.
↵2-c 10 μM MPEP was used to determine non-specific binding.