Ritanserin

The following drugs were used: L-DOPA (50 mg/kg; Sigma-Aldrich, St Louis, MO, USA), methamphetamine (METH; 1 mg/kg; Dainippon Sumitomo Pharma, Osaka, Japan), haloperidol (1 mg/kg; Sigma-Aldrich), clozapine (5 and 10 mg/kg; Toronto Research Chemicals, Toronto, ON, Canada), 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 1 mg/kg; Sigma-Aldrich), ritanserin (3 mg/kg; Sigma-Aldrich), prazosin hydrochloride (1 mg/kg; Sigma-Aldrich), pyrilamine maleate salt (20 mg/kg; Sigma-Aldrich), clonidine (0.1 mg/kg; Sigma-Aldrich), oxotremorine-M (0.1 mg/kg; Sigma-Aldrich), donepezil hydrochloride (3 mg/kg, Tokyo Chemical Industry, Tokyo, Japan), and ziprasidone hydrochloride monohydrate (3 mg/kg; Toronto Research Chemicals). L-DOPA was prepared as 1.4 mg/ml in a 2.5 mg/ml ascorbic acid solution dissolved in saline. Methamphetamine, 8-OH-DPAT, pyrilamine, clonidine, and oxotremorine-M were dissolved in saline. haloperidol and ritanserin were dissolved in 0.8% lactic acid. clozapine was dissolved in a minimum amount of 0.1 N HCl and diluted to the required doses with saline. Prazosin and donepezil were dissolved in water. Ziprasidone was prepared as a suspension in aqueous Tween-80 (1% v/v in distilled water). L-DOPA was administered i.p. in a volume of 35 ml/kg, and the other drugs were administered s.c. in a volume of 10 ml/kg.

17-β-estradiol (E2; Sigma, St Louis, MO, USA) was dissolved in safflower oil to a
concentration of 0.5 mg/mL. CFA (Sigma) was dissolved in saline at a 1:1 ratio.
OT (Sigma) was dissolved in 0.9% sterilized saline to a concentration of
50 μg/mL. The OT receptor antagonist atosiban (Sigma) was dissolved in 0.9%
sterilized saline to a final concentration of 0.1 μg/10 μL. The
5-HT_2A receptor antagonist ritanserin (Sigma) was dissolved in
20% dimethyl sulfoxide (DMSO, MP Biomedicals, Irvine, CA, USA) to a final
concentration of 20 μg/10 μL. Intrathecal administration of 20% DMSO has no
significant effect on pain behaviors in rats according to our results^{41 (link)}
and other studies.^{42 (link)}

5-Hydroxytryptamine (serotonin, 5HT), gamma-aminobutyric acid (GABA), capsaicin, ritanserin, tropisetron hydrochloride along with bulk chemicals were obtained from Sigma-Aldrich (Vienna, Austria). Bradykinin, 6-(1,1-Dimethylethyl)-2-[(2-furanylcarbonyl) amino]-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acid (CaCC Inh. - A01), SB 204741 (N-(1-Methyl-1H-5-indolyl)-N′ -(3-methyl-5-isothiazolyl)urea), thapsigargin, and XE991 (10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone) were purchased from Tocris (Bristol, UK). 4-(4-fluorobenzoyl)-1-(4phenylbutyl) piperidine (4 F 4 PP) oxalate was obtained from Santa Cruz Biotechnology, Inc. (Heidelberg, Germany), capsazepine from Sanova Pharma Ges. m. b. H. (Vienna, Austria), 8-[5-(2,4-dimethoxy-5-(4-trifluoromethylphenylsulphonamido) phenyl-5-oxopentyl]-1,3,8-triazaspiro[4,5]decane-2,4-dione (RS102221) from Szabo-Scandic (Vienna, Austria), and tetrodotoxin (TTX) from Latoxan (Valence, France).