Neurochemical basis of interleukin 2-modified discrimination behaviour

Area of Science:

• Neuroscience
• Pharmacology
• Immunology

Background:

• Interleukin 2 (IL-2) is a cytokine primarily known for its role in immune responses.
• The central nervous system effects of cytokines, including IL-2, are increasingly recognized.
• Previous research indicated that Interferon-alpha (IFN-alpha) influences drug discrimination behaviors in rats.

Purpose of the Study:

• To investigate the effects of recombinant human interleukin 2 (rIL-2) on drug discrimination in rats.
• To determine if IL-2 modulates the behavioral effects of d-amphetamine and ethylketocyclazocine (EKC).
• To explore the involvement of opioid receptors in mediating the behavioral effects of IL-2.

Main Methods:

• Rats were trained to discriminate between d-amphetamine or EKC and saline.
• Rats were administered rIL-2 prior to drug discrimination tests.
• The effects of IL-2 were assessed alone and in combination with the opioid antagonist naloxone.

Main Results:

• rIL-2 potentiated d-amphetamine-induced responses, an effect blocked by naloxone.
• rIL-2 alone produced EKC-like responses in EKC-trained rats.
• rIL-2 also potentiated EKC-induced responses, an effect also blocked by naloxone.
• These findings indicate IL-2 exerts similar neurochemical actions to IFN-alpha on d-amphetamine and EKC discrimination.

Conclusions:

• Interleukin 2 (IL-2) modulates drug discrimination behaviors in rats.
• The effects of IL-2 on d-amphetamine and EKC discrimination are mediated, at least in part, by opioid receptors.
• IL-2 shares neurochemical actions with IFN-alpha regarding these specific behavioral paradigms.