Scale bars = 100 m. that pharmacological inhibition of arrestin-2 function through GHSR1a antagonism is not equivalent Pirfenidone to the loss of arrestin-2 function achieved by genetic ablation. These data support targeting GHSR1a signaling in addiction therapy but indicate that using signaling biased compounds that modulate arrestin-2 activity differentially from G protein activity may be required. locomotor testing in WT C57BL/J6 mice exposed to graded i.p. doses of 5, 10, and 20 mg/kg YIL781 followed 15 min later by an i.p. dose of either vehicle or cocaine, Figure 2A). Each tested concentration of YIL781 significantly reduced cocaine-induced hyperlocomotion. However, post-cocaine, the total distance traveled over 30 min was significantly reduced only in the 10 and 20 mg/kg YIL781 treated mice, Figure 2B. The 10mg/kg dose of YIL781 when injected alone also did not affect basal locomotion, Figure 2C, suggesting this dose would be appropriate for subsequent behavioral testing. Open in a separate window Figure 2 Acute cocaine-induced locomotion after GIII-SPLA2 GHSR1a antagonist treatment(A) Cocaine-induced locomotion was measured in C57BL/6J YIL781 treated WT mice (n=5C6 mice/group; ANOVA: interaction P < 0.0001; treatment P < Pirfenidone 0.01). Tukey`s Pirfenidone post hoc comparisons of different doses of YIL781 and vehicle revealed significant differences at multiple time points (*p<0.05). (B) Effect of pre-treatment with 10 and 20 mg/kg YIL781 on cocaine-mediated locomotion evaluated by total distanced moved over the 30 min post-cocaine injection period (ANOVA: treatment P < 0.0006) Tukey`s post hoc test: 10mg/kg YIL781 vs saline, *p< 0.05; 20mg/kg YIL781 vs saline, ***p < 0.001; 20mg/kg YIL781 vs 5 or 10 mg/kg YIL781, #p<0.05). (C) ANOVA analysis of 10 mg/kg YIL781 treatment on locomotor activity compared to vehicle (treatment P=0.66), interaction P=0.29). We next examined the effect of YIL781 on locomotor sensitization induced by chronic cocaine administration (see methods). A subset of the C57BL/6J WT mice that received daily saline injections instead of cocaine over the sensitization period served as controls. YIL781 administration reduced cocaine-induced locomotion at multiple time points in both sensitized and control mice (Figure 3A), but the control mice demonstrated less horizontal locomotion compared to cocaine-sensitized mice at 5, 10, 15 and 20 min following the administration of 5 mg/kg cocaine (Figure 3A, symbol #). Additionally, over the 30 min interval Pirfenidone post 5 mg/kg i.p. cocaine, the 10 mg/kg YIL781 pre-treatment decreased locomotion compared to vehicle pre-treated controls (Figure 3B, symbol *). Open in a separate window Figure 3 Locomotor sensitization to cocaine in C57BL/6J mice(A) On the test day, the GHSR1a antagonist pre-treatment reduced cocaine locomotion in both saline sensitized and cocaine sensitized groups at multiple time points (n= 6 mice/group, ANOVA: interaction P < 0.0001; treatment P< 0.0001; Tukey`s post hoc test: cocaine-sensitized group compared to saline sensitized group, #p<0.05; YIL781 compared to saline pre-treatment, *p<0.05). (B) Data showing the sum of distance traveled during 30 min after cocaine administration (ANOVA: treatment P < 0.0001; Tukey`s post hoc test: cocaine-sensitized group compared to saline sensitized group, #p<0.05, ##p<0.01; YIL781 compared to saline pre-treatment, *p<0.05, **p<0.01). Rodent open field activity can be affected by either high or low blood pressure. High blood pressure delays the habituation to the arena (Sestakova, Puzserova, Kluknavsky, & Bernatova, 2013) while low blood pressure may impair motor performance and environment Pirfenidone exploration. It has been reported that peripheral injection of ghrelin and other GHSR1a agonists decrease blood pressure, and this occurs with or without a decrease in.