Fig. 1.

Light microscopic distribution of SST_2A receptor immunolabeling in claustrum slices incubated for 40 min at 37°C in Ringer's buffer (A), in Ca²⁺-free buffer (B), in Ca²⁺-free buffer containing 100 nm[d-Trp⁸]-SRIF (C), and in Ca²⁺-free buffer containing 100 nm[d-Trp⁸]-SRIF plus 10 μm PAO (D). A, After incubation in Ringer's, intense immunolabeling is observed over nerve cell bodies and their proximal dendrites (arrows). Punctate immunostaining typical of cross-sectioned immunoreactive dendrites is also evident (arrowheads).B, After incubation in Ca²⁺-free buffer, the intensity of SST_2A immunolabeling is reduced dramatically in both cell bodies and surrounding neuropil.C, Addition of 100 nm[d-Trp⁸]-SRIF to the Ca²⁺-free incubation medium almost totally reestablishes the level of SST_2A immunoreactivity to that seen in Ringer's controls. D, [d-Trp⁸]-SRIF-induced recovery of SST_2A immunoreactivity is totally prevented by addition of the endocytosis inhibitor PAO to the incubation medium. Scale bar, 100 μm.