Neurochemical basis of interleukin 2-modified discrimination behaviour.
We trained one group of rats to discriminate 0.8 mg/kg intraperitoneal (i.p.) d-amphetamine from 1 ml/kg saline and the other to discriminate 0.3 mg/kg i.p. (+/-)-ethylketocyclazocine (EKC) from saline. Recombinant human interleukin 2 (rIL-2), 2 x 10(6) U/kg (or 8.2 nmol/kg) given i.p. 1 h prior to tests, potentiated responses elicited by 0.4 mg/kg d-amphetamine. This potentiation of d-amphetamine responses was suppressed by the opioid receptor antagonist naloxone (1 mg/kg) when administered i.p. together with IL-2. IL-2 (4 x 10(6) U/kg) alone produced EKC-like responses in the EKC-trained animals. The cytokine also potentiated 0.1 mg/kg EKC responses at 2 x 10(6) U/kg, an action that was suppressed by 1 mg/kg naloxone. Data from the present study show that IL-2 exerts the same neurochemical action as that previously observed with IFN-alpha for both d-amphetamine and EKC discrimination in rats.
Ho
B T
BT
Department of Neuro-Oncology, University of Texas, M.D. Anderson Cancer Center, Houston 77030.
Lu
J G
JG
Huo
Y Y
YY
Fan
S H
SH
Meyers
C A
CA
Tansey
L W
LW
Payne
R
R
Levin
V A
VA
D000818:Animals; D003913:Dextroamphetamine / Q000494:pharmacology; D004193:Discrimination Learning / Q000187:drug effects*; D015259:Dopamine Agents / Q000494:pharmacology; D016314:Ethylketocyclazocine / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011957:Receptors, Opioid / Q000187:drug effects
D015259:Dopamine Agents; D007376:Interleukin-2; D011957:Receptors, Opioid; D016314:Ethylketocyclazocine; D003913:Dextroamphetamine