2. Academic Validation
  3. Effects of the neuropeptide S receptor antagonist RTI-118 on abuse-related facilitation of intracranial self-stimulation produced by cocaine and methylenedioxypyrovalerone (MDPV) in rats

Effects of the neuropeptide S receptor antagonist RTI-118 on abuse-related facilitation of intracranial self-stimulation produced by cocaine and methylenedioxypyrovalerone (MDPV) in rats

  • Eur J Pharmacol. 2014 Nov 15;743:98-105. doi: 10.1016/j.ejphar.2014.09.006.
Julie S Bonano 1,  Scott P Runyon 2,  Carla Hassler 2,  Richard A Glennon 3,  S Stevens Negus 4
Affiliations

Affiliations

  • 1 Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, PO Box 980613, Richmond, VA 23298, USA. Electronic address: [email protected].
  • 2 Organic and Medicinal Chemistry, Research Triangle Institute, 3040 East Cornwallis Road, PO Box 12194, Research Triangle Park, NC 27709, USA.
  • 3 Department of Medicinal Chemistry, Virginia Commonwealth University, 1101 East Marshall Street, PO Box 980551, Richmond, VA 23298, USA.
  • 4 Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, PO Box 980613, Richmond, VA 23298, USA.
PMID: 25220242 DOI: 10.1016/j.ejphar.2014.09.006
Abstract

Neuropeptide S (NPS) is a neurotransmitter that activates the NPS receptor to modulate biological functions including anxiety-like behaviors, feeding, and drug reinforcement. RTI-118 is a novel NPS receptor antagonist that decreased cocaine self-administration in rats at doses that had little or no effect on food-maintained responding. To build on these previous findings, this study examined effects of RTI-118 on cocaine-induced facilitation of intracranial self-stimulation (ICSS) in rats. To provide a context for data interpretation, effects of RTI-118 were compared to effects of the kappa Opioid Receptor Agonist U69,593, because the kappa Opioid Receptor is another peptide neurotransmitter receptor reported to modulate abuse-related cocaine effects. RTI-118 effects were also examined on ICSS facilitation produced by methylenedioxypyrovalerone (MDPV), a novel designer drug of abuse with some cocaine-like effects. Male Sprague-Dawley rats (n=12) with electrodes targeting the medial forebrain bundle responded under a fixed-ratio 1 schedule for range of brain stimulation frequencies. Under control conditions, brain stimulation maintained a frequency-dependent increase in ICSS rates. Cocaine (1.0-10mg/kg) and MDPV (3.2mg/kg) facilitated ICSS. RTI-118 (3.2-32mg/kg) alone produced little effect on ICSS but dose dependently blocked cocaine-induced ICSS facilitation. U69,593 (0.25-0.5mg/kg) also attenuated cocaine effects, but blockade of cocaine effects was incomplete even at a U69,593 dose that alone depressed ICSS. RTI-118 (32mg/kg) failed to block MDPV-induced ICSS facilitation. These results support further consideration of NPS receptor antagonists as candidate treatments for cocaine abuse and provide evidence for differential effects of a candidate treatment on abuse-related effects of cocaine and MDPV.

Keywords

Cocaine; Intracranial self-stimulation; Methylenedioxypyrovalerone; Neuropeptide S; RTI-118.

Figures
Products