Figure 3
From: Somatostatin triggers rhythmic electrical firing in hypothalamic GHRH neurons
SST acts through sst1 and sst2 to inhibit GHRH neuron activity.
(A) 100 nM Octreotide superfusion suppresses action potential firing frequency in male GHRH-GFP neurons. (B) As for (A) but female animals. (C) Mean traces showing GHRH neuron action potential firing kinetics in male animals following application of the sst2 agonist octreotide (n = 16). Frequencies are normalized (1 = max, 0 = min). Grey (P > 0.01) and white (P < 0.01) shaded areas indicate significant differences in GHRH population electrical activity versus control (hatched line) (paired Student’s t test). (D) As for (C) but female mice (n = 12). (E) Bath application of the sst1 agonist CH-275 does not alter GHRH neuron action potential firing rate in male animals. SST was used as a positive control. (F) As for (E) but female animals. (G) Mean traces showing delayed recovery from octreotide suppression in CH-275 treated male GHRH neurons (n = 13). (H) As for (G) but showing appearance of recurrent spiking activity in females (n = 15). In all cases, compounds were introduced at t = 0 min. The control action potential frequencies were 3.22 ± 0.8 Hz in (C); 1.38 ± 0.2 Hz in (D); 1.53 ± 0.4 Hz in (G); and 1.97 ± 0.4 Hz in (H).
