Cocaine hydrochloride (provided by the National Institute on Drug Abuse) was dissolved in 0.9% physiological saline and sterile filtered through a 0.2μm filter (ThermoScientific). Cocaine was diluted to a dose of 1 mg/kg delivered in a volume of 0.1 ml over a period of 4.3 s via a 10ml syringe nested in a motorized syringe pump (Razel Scientific Instruments). The dose of 1 mg/kg i.v. cocaine was chosen based upon the results of previous runway work from our laboratory (Raven et al 2000 (link); Ettenberg 2004 (link); Ettenberg and Bernardi 2006 (link); Wenzel et al 2011 (link); 2014 (link)).
The 5-HT1B agonist CP 94,253 dihydrochloride (Sigma-Aldrich) was prepared in a vehicle solution of aCSF (l-Ascorbic Acid 0.35g/L, NaCl 8.47g/L, KCl .20g/L, MgCl2 .20g/L, CaCl2 .18g/L, NaH2PO4 .276g/L, Na2HPO4 .5362g/L) for intracranial infusion at the concentrations 0.25, 0.5, or 1.0μg/0.5μl. CP 94,253 was selected as it shows the greatest affinity for 5-HT1B over other receptors in the 5-HT1 family (Koe et al 1992 ). Utilized doses were determined from prior studies reporting behavioral effects with intracerebral administration (De Almeida et al 2006 (link); Veiga and Miczek 2007 ). The selective 5-HT1B antagonist NAS-181 (Stenfors et al 2000 (link); De Groote et al 2002 (link); 2003 (link)) was prepared in the same vehicle as CP 94,253 and infused at doses of 0.1μg or 1.0μg per 0.5μl/side.
The 5-HT1B agonist CP 94,253 dihydrochloride (Sigma-Aldrich) was prepared in a vehicle solution of aCSF (l-Ascorbic Acid 0.35g/L, NaCl 8.47g/L, KCl .20g/L, MgCl2 .20g/L, CaCl2 .18g/L, NaH2PO4 .276g/L, Na2HPO4 .5362g/L) for intracranial infusion at the concentrations 0.25, 0.5, or 1.0μg/0.5μl. CP 94,253 was selected as it shows the greatest affinity for 5-HT1B over other receptors in the 5-HT1 family (Koe et al 1992 ). Utilized doses were determined from prior studies reporting behavioral effects with intracerebral administration (De Almeida et al 2006 (link); Veiga and Miczek 2007 ). The selective 5-HT1B antagonist NAS-181 (Stenfors et al 2000 (link); De Groote et al 2002 (link); 2003 (link)) was prepared in the same vehicle as CP 94,253 and infused at doses of 0.1μg or 1.0μg per 0.5μl/side.
