Fig. 2.
Group I and III mGluRs also activate GIRK.A, In an oocyte coexpressing mGluR1a and Kir3.1 plus Kir3.4, application of glutamate (Glu; 100 μm) activated a transient endogenousICaCl that overlapped the GIRK current. However, ICaCl desensitized on subsequent applications of glutamate, allowing GIRK responses to be seen in isolation. B, In an oocyte pretreated with BAPTA-AM (0.5 mm, 30 min), ICaCl currents were reduced significantly in amplitude with the first application of glutamate. The underlying GIRK responses showed no desensitization on repeated application of glutamate. C, GIRK responses were also observed in an oocyte coexpressing mGluR7 with Kir3.1 plus Kir3.4 after application of 2 mm DL-AP4 (AP4).