Abstract
In membranes of undifferentiated neuroblastoma × glioma hybrid cell line NG108‐15, the apparent specific binding of [3H]yohimbine measured in the presence of 1 μM noradrenaline, was increased substantially by the presence of the poorly hydrolysed analogue of QTP, guanylyl‐imidodiphosphate (Gpp[NH]p) or by preincubation of membranes with antibodies against the C‐terminal decapeptide of the α subunit of the G‐protein Gi2. Such an effect was not produced by antibodies against the equivalent region of Goα Gi3α or Gsα or from non‐immune serum. By contrast, total specific binding of [3H]yohimbine was not modified by co‐incubation with Gpp[NH]p or by preincubation with the antibodies from any of the anti‐G protein antisera. These results demonstrate a direct interaction of the α2B adrenergic receptor of NG108‐15 cells with Gi2.