Locus Coeruleus-mediated transcriptomic changes in the hippocampus.
a, Experimental design for assessing LC activation and cortical NA release induced by injection of yohimbine (3 mg/kg, i.p.). b, Representative images and quantification of LC activation in mice 90 min after injection of vehicle or yohimbine as measured by cFos (red) and tyrosine hydroxylase (TH, green) coexpression within LC neurons. Yohimbine injection increased cFos expression within LC neurons compared to vehicle-injected animals (unpaired t test; t(8.9) = −8.814, p = 1.083e-05). Vehicle, n = 4; Yohimbine n = 7. Scale bar: 100μm. c, Experimental design for comparing molecular changes in the hippocampus after acute swim stress exposure or yohimbine administration. d, Volcano plots showing differentially expressed RNA transcripts in the dorsal (dHC) and ventral (vHC) hippocampus between control (Veh) and yohimbine (Yoh) injected animals 45 min after injection. Red and blue values represent changes with FDR-adjusted p<0.05 (Veh n = 6, Yoh n = 6). e, Strength of the yohimbine effect in comparison to the transcriptomic stress response. Data are sorted by interaction strength in the stress group (orange) and the corresponding interaction strength of the yohimbine group are shown in dark red for the same gene. f, Experimental design for assessing LC activation and hippocampal transcriptomic changes induced by chemogenetic LC activation. g, Representative images and quantification of LC activation in mice 45 min after injection of clozapine (0.03 mg/kg) in hM3Dq- and hM3Dq+ animals as measured by cFos (green) and tyrosine hydroxylase (TH, red) coexpression within LC neurons. Neurons are stained with Nissl (blue). Clozapine injection increased cFos expression within LC neurons in hM3Dq+ animals compared to hM3Dq-animals (one way ANOVA; F(3, 23) = 135.4, p = 9.34e-15). hM3Dq-n = 6, hM3Dq+ n = 7. Scale bar: 100μm. h, Volcano plots showing differentially expressed RNA transcripts between hM3Dq- and hM3Dq+ animals 45 min after injection of clozapine (0.03 mg/kg) in the dHC and vHC. Red and blue values represent changes with FDR-adjusted p<0.05 (hM3Dq- n = 6, hM3Dq+ n = 7). i, Experimental design for assessing LC activation, cortical NA release, pupillometry and hippocampal transcriptomic changes induced by optogenetic 5 Hz LC activation. j, Representative images and quantification of LC activation in mice after 5 Hz optogenetic LC activation as measured by cFos (red) and tyrosine hydroxylase (TH, green) coexpression within LC neurons in stimulated and non-stimulated LC hemispheres of ChR2- and ChR2+ animals. 5 Hz stimulation increased cFos expression within LC neurons in stimulated LC hemispheres of ChR2+, but not in ChR2-animals 45 min (one-way ANOVA with Tukey’s post hoc tests; F(3, 14) = 12.91, p = 0.000256) and 90 min after stimulation onset (one way ANOVA with Tukey’s post hoc tests; F(3, 14) = 5.866, p = 0.00824). ChR2- (45 min), n = 5; ChR2- (90 min), n = 5; ChR2+ (45 min), n = 4; ChR2+ (90 min), n = 4. Scale bar: 100μm. k, Quantification of cortical MHPG/NA ratio, as measured by uHPLC, after 5 Hz optogenetic LC activation in ChR2- and ChR2+ animals. 5 Hz stimulation increased cortical NA turnover in ChR2+ animals (unpaired t test; 45 min: t(3.6) = 8.444, p = 0.001681; 90 min: t(4.0854) =3.4127, p = 0.02608). ChR2-45min, n = 5; ChR2-90min, n = 5; ChR2+ 45min, n = 6; ChR2+ 90min, n = 5. l, Average pupil size changes in response to 5 Hz optogenetic LC activation in ChR2- and ChR2+ animals. 5 Hz stimulation increased pupil size in ChR2+, but not ChR2-animals. m, Volcano plots showing differentially-expressed RNA transcripts between ChR2- and ChR2+ animals 45 and 90 min after 5 Hz optogenetic LC activation in the ventral (vHC) hippocampus. Red and blue values represent changes with FDR-adjusted p<0.05 (ChR2- n = 10, ChR2+ n = 11). n, Heatmap showing genes that are commonly differentially expressed by yohimbine, chemogenetic and optogenetic induced LC activation. o, Logarithmic cumulative rank of genes across all experiments from figure 1 and 2 in terms of their NA responsiveness. A lower cumulative rank indicates that a gene is among the more significant hits across all analyses (for full list of included analyses see methods). Labels indicate the 10 genes identified to be most responsive to LC-NA stimulation. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.