Animal experiment:

Rats: GSK1059865 is dissolved in 0.5% HPMC (w/v) in distilled water and administered by gavage at doses of 10 and 30 mg/kg to rats. Drug or vehicle is administered 1 h before access to highly palatable food[2]. Mice: During baseline and the first 5 test cycles following chronic intermittent ethanol (or air) exposure, mice receive vehicle (saline) injections (i.p.; 0.01 ml/g body weight) 30 minutes before drinking ethanol. On test cycles 6 and 7 mice receive vehicle or GSK1059865 (10, 25, 50 mg/kg) before given access to ethanol 15% v/v (Test 6) or sucrose 5% w/v (Test 7) versus water. GSK1059865 is dissolved in saline and TWEEN 80 (0.5 % v/v) as vehicle[1].

GSK1059865 is a potent orexin 1 receptor antagonist.

Treatment with GSK1059865 significantly decreases ethanol drinking in a dose-dependent manner in CIE-exposed mice. In contrast GSK1059865 decreases drinking in air-exposed mice only at the highest dose used. There is no effect of GSK1059865 on sucrose intake[1]. GSK1059865 (0.3 nM-10 nM) produces non-surmountable antagonism with a dose-dependent rightward shift of the OXA EC50 and a concomitant decrease of the agonist maximal response. The calculated pKB value is 8.77±0.12 for GSK1059865. GSK1059865 (0.1-3.3 μM) produces a classical surmountable profile with parallel rightward shift of the OXA EC50 without depression of the agonist maximal response[2]. Intraperitoneal administration of GSK1059865 produces a region-dependent inhibition of yohimbine-induced relative cerebral blood volume response. The administration of GSK1059865 per se produces a weak relative cerebral blood volume increase in several brain regions. GSK1059865-pretreated animals exhibit slightly higher baseline mean arterial blood pressure values than controls[3].

[1]. Lopez MF, et al. The highly selective orexin/hypocretin 1 receptor antagonist GSK1059865 potently reduces ethanol drinking in ethanol dependent mice. Brain Res. 2016 Apr 1;1636:74-80. [2]. Piccoli L, et al. Role of orexin-1 receptor mechanisms on compulsive food consumption in a model of binge eating in female rats. Neuropsychopharmacology. 2012 Aug;37(9):1999-2011. [3]. Gozzi A, et al. Differential effect of orexin-1 and CRF-1 antagonism on stress circuits: a fMRI study in the rat with the pharmacological stressor Yohimbine. Neuropsychopharmacology. 2013 Oct;38(11):2120-30.