Nucleus accumbens injections of the mGluR2/3 agonist LY379268 increase cue-induced sucrose seeking following adult, but not adolescent sucrose self-administration
| Autor: | Stephanie E. Myal, Patricio O'Donnell, Danielle S. Counotte |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Agonist
Male medicine.medical_specialty Sucrose medicine.drug_class media_common.quotation_subject Self Administration AMPA receptor Nucleus accumbens Article Nucleus Accumbens chemistry.chemical_compound Internal medicine medicine Excitatory Amino Acid Agonists Animals Rats Long-Evans Excitatory Amino Acid Agonist Amino Acids media_common Analysis of Variance Alanine Dose-Response Relationship Drug General Neuroscience Antagonist Feeding Behavior Abstinence Bridged Bicyclo Compounds Heterocyclic Rats Endocrinology chemistry Anesthesia NMDA receptor Conditioning Operant Cues Self-administration Psychology Excitatory Amino Acid Antagonists |
| Popis: | Adolescence is often portrayed as a period of enhanced sensitivity to reward, with long-lasting neurobiological changes upon reward exposure. However, we previously found that time-dependent increases in cue-induced sucrose seeking were more pronounced in rats trained to self-administer sucrose as adults than as adolescents. In addition, adult, but not adolescent sucrose self-administration led to a decreased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/N-Methyl-D-aspartate (AMPA/NMDA) ratio in the nucleus accumbens core, suggesting that long-lasting changes in glutamatergic transmission may affect adult processing of natural rewards. Here we tested whether altering glutamatergic transmission in the nucleus accumbens core via local injection of an mGluR2/3 agonist and antagonist affects cue-induced sucrose seeking following abstinence and whether this is different in the two age groups. Rats began oral sucrose self-administration training (10 days) on postnatal day (P) 35 (adolescents) or P70 (adults). Following 21 days of abstinence, rats received microinjections of the mGluR2/3 agonist LY379268 (0.3 or 1.0 μg/side) or vehicle into the nucleus accumbens core, and 15 min later cue-induced sucrose seeking was assessed. An additional group of rats trained as adults received nucleus accumbens core microinjections of the mGluR2/3 antagonist (RS)-α-Methyl-4-phosphonophenylglycine (MPPG) (0.12 or 0.5 μg/side). Confirming our previous results, adult rats earned more sucrose reinforcers, while sucrose intake per body weight was similar across ages. On abstinence day 22, local injection of the mGluR2/3 agonist LY379268 increased cue-induced sucrose seeking only in adult rats, and had no effect in adolescents. Local injections of the mGluR2/3 antagonist MPPG had no effect on sucrose seeking in adult rats. These data suggest an important developmental difference in the neural substrates of natural reward, specifically a difference in glutamatergic transmission in the accumbens in cue-induced responding for sucrose between adolescent and adult rats. |
| Databáze: | OpenAIRE |
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