TABLE 1

Equilibrium dissociation constants (expressed as pKi values) for mGlu5 receptor PAMs in the absence and presence of quisqualate (30 μM) in membranes prepared from cortical astrocytes or rat cortex

Data are shown as means ± S.E.M. for five to seven experiments in the absence of quisqualate and three experiments in the presence of quisqualate all performed in duplicate. Also shown is the shift in pKi value in the presence and absence of quisqualate and its antilogarithm, which represents the affinity cooperativity (α) between the PAM and agonist.

pKiΔpKi (logα)α
Control+Quisqualate
Astrocytes
    DFB5.28 ± 0.045.47 ± 0.01*0.191.5
    CPPHA6.37 ± 0.236.06 ± 0.00N.D.N.D.
    CDPPB5.92 ± 0.086.96 ± 0.06***1.0411
    ADX472735.18 ± 0.035.68 ± 0.06**0.503.2
Rat cortex
    DFB5.41 ± 0.055.49 ± 0.120.081.2
    CPPHA6.02 ± 0.086.23 ± 0.11N.D.N.D.
    CDPPB6.39 ± 0.126.97 ± 0.08*0.583.8
    ADX472735.51 ± 0.085.81 ± 0.05*0.302.0

  • N.D., value not determined for CPPHA because it is not competitive with respect to MPEP.

  • ↵* P < 0.05, unpaired Student's t test.

  • ↵** P < 0.01, unpaired Student's t test.

  • ↵*** P < 0.001, unpaired Student's t test.