The G protein biased serotonin 5-HT2A receptor agonist lisuride exerts anti-depressant drug-like activities in mice

Abstract

There is now evidence from multiple Phase II clinical trials that psychedelic drugs can exert long-lasting anxiolytic, anti-depressant, and anti-drug abuse (nicotine and ethanol) effects in patients. Despite these benefits, the hallucinogenic actions of these drugs at the serotonin 2A receptor (5-HT2AR) limit their clinical use in diverse settings. Activation of the 5-HT2AR can stimulate both G protein and β-arrestin (βArr) -mediated signaling. Lisuride is a G protein biased agonist at the 5-HT2AR and, unlike the structurally-related lysergic acid diethylamide (LSD), the drug does not typically produce hallucinations in normal subjects at routine doses. Here, we examined behavioral responses to lisuride, in wild-type (WT), βArr1-knockout (KO), and βArr2-KO mice. In the open field, lisuride reduced locomotor and rearing activities, but produced a U-shaped function for stereotypies in both βArr lines of mice. Locomotion was decreased overall in βArr1-KOs and βArr2-KOs relative to wild-type controls. Incidences of head twitches and retrograde walking to lisuride were low in all genotypes. Grooming was decreased in βArr1 mice, but was increased then decreased in βArr2 animals with lisuride. Serotonin syndrome-associated responses were present at all lisuride doses in WTs, but they were reduced especially in βArr2-KO mice. Prepulse inhibition (PPI) was unaffected in βArr2 mice, whereas 0.5 mg/kg lisuride disrupted PPI in βArr1 animals. The 5-HT2AR antagonist MDL100907 failed to restore PPI in βArr1 mice, whereas the dopamine D2/D3 antagonist raclopride normalized PPI in WTs but not in βArr1-KOs. Clozapine, SCH23390, and GR127935 restored PPI in both βArr1 genotypes. Using vesicular monoamine transporter 2 mice, lisuride reduced immobility times in tail suspension and promoted a preference for sucrose that lasted up to 2 days. Together, it appears βArr1 and βArr2 play minor roles in lisuride's actions on many behaviors, while this drug exerts anti-depressant drug-like responses without hallucinogenic-like activities.

Keywords: head twitch; lisuride; mice; prepulse inhibition; serotonin 2A receptor; serotonin-syndrome; β-arrestin.

FIGURE 1

Effects of lisuride on cumulative motor activities in β-arrestin 1 mice. Baseline activities were monitored from 0 to 30 min, animals were given vehicle (Veh) or various doses of lisuride, and returned to the open field for 90 min. (A) Cumulative distance traveled. Baseline: no significant effects. Post-injection: two-way ANOVA for genotype [F (1,161) = 4.050, p = 0.046] and treatment [F (7,161) = 33.270, p < 0.001]. (B) Vertical counts (rearing). Baseline: two-way ANOVA for genotype [F (1,161) = 7.636, p = 0.006] and treatment [F (7,161) = 5.384, p < 0.001]. Post-administration: two-way ANCOVA for treatment [F (7,160) = 27.412, p < 0.001]. (C) Stereotypies. Baseline: two-way ANOVA for treatment [F (7,161) = 3.298, p = 0.003]. Following injection: two-way ANCOVA for treatment [F (7,160) = 14.609, p < 0.001]. Data presented as means ±SEMs; n = 8–15 mice/genotype/treatment; *p < 0.05, WT vs. KO; ⁺ p< 0.05, ⁺⁺ p< 0.01, vs. Vehicle.

FIGURE 2

Effects of lisuride on cumulative motor activities in β-arrestin 2 mice. The procedure is identical to Figure 1. (A) Cumulative distance traveled. Baseline: no significant effects. Post-injection: two-way ANOVA for genotype [F (1,157) = 11.710, p < 0.001] and treatment [F (7,157) = 25.825, p < 0.001]. (B) Vertical counts (rearing). Baseline: two-way ANOVA for treatment [F (7,157) = 8.162, p < 0.001]. Post-administration: two-way ANCOVA for treatment [F (7,156) = 18.319, p < 0.001]. (C) Stereotypical activities. Baseline: two-way ANOVA for genotype [F (1,157) = 4.205, p = 0.042] and treatment [F (7,157) = 10.009, p < 0.001]. Following injection: two-way ANCOVA for treatment [F (7,156) = 8.485, p < 0.001]. Data presented as means ±SEMs; n = 10–15 mice/genotype/treatment. ***p < 0.001, WT vs. KO; ⁺ p< 0.05, ⁺⁺⁺ p< 0.001, vs. Vehicle.

FIGURE 3

Serotonin syndrome-associated behaviors and head twitch responses with lisuride in β-arrestin 1 and β-arrestin 2 mice. Responses were scored over the initial 30-min post-injection period. (A) Lisuride dose-response induced 5-HT syndrome-associated behaviors in β-arrestin 1 mice. Two-way ANOVA for treatment [F (7,161) = 26.264, p < 0.001] and genotype by treatment interaction [F (7,161) = 3.918, p < 0.001]; n = 8–15 mice/genotype/treatment. (B) Lisuride dose-response induced 5-HT syndrome-associated behaviors in β-arrestin 2 mice. Two-way ANOVA for genotype [F (1,157) = 153.263, p < 0.001], treatment [F (7,157) = 22.422, p < 0.001], and genotype by treatment interaction [F (7,157) = 7.193, p < 0.001]; n = 10–15 mice/genotype/treatment. (C) Head twitch responses in βArr1 mice given different doses of lisuride and 0.3 mg/kg LSD. Two-way ANOVA for treatment [F (8,177) = 89.256, p < 0.001]; n = 8–15 βArr1 mice/genotype/treatment. (D) Head twitch responses in βArr2 mice receiving the same treatments as panel C. Two-way ANOVA for genotype [F (1,175) = 23.388, p < 0.001], treatment [F (8,175) = 57.323, p < 0.001], and genotype by treatment interaction [F (8,175) = 13.667, p < 0.001]; n = 10–15 βArr2 mice/genotype/treatment. The data are presented as means ±SEMs. ***p < 0.001, WT vs. KO for Lisuride or 0.3 mg/kg LSD; ⁺ p< 0.05, ⁺⁺⁺ p< 0.001, vs. Vehicle; ^‡‡‡ p < 0.001, vs. 0.01 mg/kg Lisuride; ^¶ p < 0.05, vs. 1 mg/kg Lisuride; ^† p < 0.05, vs. 2 mg/kg Lisuride; ^{^} p < 0.05, ^{^^} p < 0.01, ^{^^^} p < 0.001, vs. 4 mg/kg Lisuride; ^ΔΔΔp<0.001, vs. LSD.

FIGURE 4

Effects of lisuride on prepulse inhibition in β-arrestin 1 mice. Animals were administered vehicle, 0.5 mg/kg MDL100907, 3 mg/kg raclopride, or 0.5 mg/kg clozapine before giving vehicle or lisuride and tested. (A) PPI in βArr 1 mice receiving vehicle or different lisuride doses. RMANOVA for PPI [F (2,164) = 406.059, p < 0.001], PPI by treatment interaction [F (6,164) = 7.644, p < 0.001], and treatment [F (3,82) = 8.814, p < 0.001]; n = 10–16 βArr1 mice/genotype/treatment. (B) PPI in βArr1 mice treated with vehicle, 0.5 mg/kg MDL100907, 0.5 mg/kg lisuride, or MDL100907 plus lisuride. RMANOVA for PPI [F (2,158) = 368.350, p < 0.001], PPI by treatment interaction [F (6,158) = 6.158, p < 0.001], and treatment [F (3,79) = 14.448, p < 0.001]; n = 9–16 βArr1 mice/genotype/treatment. (C) PPI in βArr1 mice given vehicle, 3 mg/kg raclopride, 0.5 mg/kg lisuride, or raclopride plus lisuride. RMANOVA for PPI [F (2,152) = 450.960, p < 0.001], PPI by treatment interaction [F (6,152) = 8.922, p < 0.001], PPI by genotype by treatment interaction [F (6,152) = 5.510, p < 0.001], and treatment [F (3,76) = 22.609, p < 0.001]. Deconstruction of the 3-way interaction with univariate tests for WT [F (3,76) = 9.933, p < 0.001] and βArr1-KO mice [F (3,76) = 14.798, p < 0.001]; n = 8–16 βArr1 mice/genotype/treatment. (D) PPI in βArr1 mice administered vehicle, 0.5 mg/kg clozapine, 0.5 mg/kg lisuride, or clozapine plus lisuride. RMANOVA for PPI [F (2,160) = 339.837, p < 0.001], PPI by treatment interaction [F (6,160) = 5.079, p < 0.001], PPI by genotype by treatment interaction [F (6,160) = 2.191, p = 0.046], and treatment [F (3,80) = 13.641, p < 0.001]; n = 8–16 βArr1 mice/genotype/treatment. ^# p < 0.05, ^## p < 0.01, ^### p < 0.001, vs. Vehicle + Lisuride; ^xp < 0.05, ^xxxp<0.001, Antagonist + Lisuride.

FIGURE 5

Effects of lisuride on prepulse inhibition in β-arrestin 1 and β-arrestin 2 mice. β-Arrestin 1 animals were administered vehicle, SCH23390, or GR127935 before giving vehicle or lisuride and tested. β-Arrestin 2 mice were injected with vehicle or different doses of lisuride and tested. (A) PPI in βArr1 animals given vehicle, 0.1 mg/kg SCH23390, 0.5 mg/kg lisuride, or SCH23390 plus lisuride. RMANOVA for PPI [F (2,150) = 334.367, p < 0.001], PPI by treatment interaction [F (6,150) = 5.705, p < 0.001], and treatment [F (3,75) = 19.741, p < 0.001]; n = 8–16 βArr1 mice/genotype/treatment. (B) PPI in βArr1 animals injected with vehicle, 2 mg/kg GR127935, 0.5 mg/kg lisuride, or GR127935 plus lisuride. RMANOVA for PPI [F (2,146) = 345,361, p < 0.001], PPI by treatment interaction [F (6,146) = 4.542, p < 0.001], and treatment [F (3,73) = 9.015, p < 0.001]; n = 8–16 βArr1 mice/genotype/treatment. (C) PPI in βArr 2 animals given vehicle or different doses of lisuride. RMANOVA for PPI [F (2,150) = 132.746, p < 0.001] and PPI by treatment interaction [F (6,150) = 2.485, p = 0.025]; n = 9–12 βArr2 mice/treatment. Data presented as means ±SEMs. ^‡‡‡ p < 0.001, vs. Antagonist + Vehicle; ^## p < 0.01, ^### p < 0.001, vs. Vehicle + Lisuride.

FIGURE 6

Effects of lisuride in tests of depressive-like behaviors in VMAT2 mice. In a two-bottle test, mice were presented with a water-water (W–W) pairing on day 1 and sucrose-water (S–W) pairings on days (D) 2–6; effects of vehicle (Veh) and lisuride (Lis) were examined. (A) Sucrose preference in VMAT2 mice. RMANOVA for day [F (5,110) = 8.939, p < 0.001], day by genotype interaction [F (5,110) = 9.414, p < 0.001], and genotype [F (1,22) = 7.863, p = 0.010]. (B) Total fluid intake. RMANOVA for day [F (5,110) = 21.585, p < 0.001]; n = 10–14 mice/genotype/treatment. **p < 0.01, ***p < 0.001, WT vs. VMAT2-HET; ^ ^^p < 0.01, vs. Days 1–3. (C) Tail suspension (6 min test). RMANOVA for immobility in WT mice: day by treatment interaction [F (12,123) = 2.758, p = 0.002] and treatment [F (4,41) = 4.591, p = 0.004]. RMANOVA for immobility in VMAT2-HET mice: day [F (3,120) = 26.715, p < 0.001], day by treatment interaction [F (12,120) = 2.901, p = 0.001], and treatment [F (4,40) = 8.027, p < 0.001]; n = 9–10 mice/genotype//treatment. All data presented as means ±SEMs. ⁺ p< 0.05, ⁺⁺ p< 0.01, vs. Vehicle; ^vp < 0.05, vs. Fluoxetine; ^Δp<0.05, ^ΔΔp<0.01, vs. LSD.