Adenosine agonists CGS 21680 and NECA inhibit the initiation of cocaine self-administration

• Published in: Pharmacology, biochemistry and behavior biochemistry and behavior, 2001-04, Vol.68 (4), p.797-803
• Main Authors: Knapp, Clifford M, Foye, Melissa M, Cottam, Nicole, Ciraulo, Domenic A, Kornetsky, Conan
• Format: Article
• Language: English
• Subjects: Adenosine - analogs & derivatives; Adenosine - pharmacology; Adenosine - therapeutic use; Adenosine receptors; Adenosine-5'-(N-ethylcarboxamide) - pharmacology; Adenosine-5'-(N-ethylcarboxamide) - therapeutic use; Animals; Antihypertensive Agents - pharmacology; Antihypertensive Agents - therapeutic use; Behavior, Addictive - drug therapy; Biological and medical sciences; Cocaine; Cocaine - administration & dosage; Dopamine Uptake Inhibitors - administration & dosage; Drug addictions; Infusions, Intravenous; Male; Medical sciences; Phenethylamines - pharmacology; Phenethylamines - therapeutic use; Purinergic P1 Receptor Agonists; Rats; Rats, Wistar; Reaction Time - drug effects; Reaction Time - physiology; Self Administration; Toxicology; Vasodilator Agents - pharmacology; Vasodilator Agents - therapeutic use
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/S0091-3057(01)00486-5

Administration of the adenosine antagonist caffeine will facilitate the reinstatement of cocaine self-administration responding. This suggests that adenosine receptors may play a role in the motivational systems that regulate cocaine-seeking behaviors. If so then adenosine agonists may act to block cocaine self-administration. To test this hypothesis, the effects of the nonselective adenosine agonist NECA and of the A 2A selective agonist, CGS 21680 on the self-administration of cocaine were determined. In these experiments, rats were allowed to obtain intravenous cocaine infusions (0.6 mg/kg/infusion) delivered under a Fixed Ratio 5 schedule. Treatment with either NECA or CGS 21680 in comparison to vehicle administration reduced the number of infusions received per session. This, primarily, was due to a marked increase in the latency for delivery of the first cocaine infusion. Responding after drug-induced delays tended to be at control levels. Adenosine agonists are known to have sedative effects and these actions might play a role in NECA and CGS 21680-induced increases in latencies for cocaine delivery. These results indicate that the administration of adenosine agonists may inhibit cocaine-seeking behaviors. The degree to which these actions are on motivational systems as opposed to involving less specific effects remains to be fully elucidated.