Way100135

Escitalopram was received as a gift from Lundbeck A/S, Valby, Denmark, and dissolved in saline (0.9% NaCl) at 0.1 mg/mL concentration. WAY100135 was purchased from Sigma-Aldrich s.r.o. and dissolved in saline at 0.1 mg/mL concentration. When a 5-HT neuron was identified, its basal firing activity was recorded for 2 minutes and 0.1 mg/kg escitalopram was then administered via the tail vein catheter. After 2 minutes, WAY100135 was administered i.v. in a 0.1-mg/kg dosage. The doses of escitalopram and WAY100135 were chosen according to a previous study (El Mansari et al., 2005 ), which reported that i.v. administration of 0.1 mg/kg of escitalopram completely inhibited 5-HT neurons in the DRN of Sprague-Dawley rats, and subsequent administration of 0.1 mg/kg WAY100135 reversed the escitalopram-induced inhibition of 5-HT neurons.

Trans-anethole (ANE) was obtained from Sigma Co. (USA). Its linear formula is CH₃CH = CHC₆H₄OCH₃, with formula weight of 148.20. According to Sigma report, the degree of purity is > 99%. In addition, sulpiride (Sul; a specific D₂ dopamine antagonist), reserpine (Res; a vesicular monoamine depleter), SCH-23390(SCH; a specific D₁ dopamine antagonist), WAY-100135 (WAY, a specific 5-HT_1A antagonist) ketanserin (Ket; a specific 5HT_2A/C blocker), and p-chlorophenylalanine (pCPA; a tryptophan hydroxylase inhibitor), and haloperidol (Hal; as non-specific dopamine antagonist) were obtained from Sigma Co. (USA). Yohimbine (Yoh; an α₂-adrenoceptor antagonist) and prazosin (Praz; an α₁-adrenoceptor antagonist) were obtained from Iran Daru and Razak Co. (Iran), respectively. Moreover, imipramine (Imp) and fluoxetine (Flx) were obtained from Pars Darou Co. (Iran). All drugs and ANE were given through the intraperitoneal (i.p.) route, in a volume 0.2 ml/20 g body weight. Moreover, the solvent of ANE or drugs was normal saline (0.9%) plus DMSO (5%). A vehicle-treated control received normal saline plus DMSO (5%).